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Artificial intelligence (AI) promises transformative impacts on society, industry, and agriculture, while being heavily reliant on diverse, quality data. The resource-intensive "data
problem" has initialized a shift to synthetic data. One downside of synthetic data is known as the "reality gap", a lack of realism. Hybrid data, combining synthetic and real data, addresses this. The paper examines terminological inconsistencies and proposes a unified taxonomy for real, synthetic, augmented, and hybrid data. It aims to enhance AI training datasets in smart agriculture, addressing the challenges in the agricultural data landscape. Utilizing hybrid data in AI models offers improved prediction performance and adaptability.
Compliance of agricultural AI systems : app-based legal verification throughout the development
(2024)
Significant advances in artificial intelligence (AI) have been achieved; however, practical implementation in agriculture remains limited. Compliance with emerging regulations, such as the EU AI Act and GDPR, is now vital, even for non-critical AI systems. Developers need tools to assess legal compliance, which is complex, often requiring full legal advice. To address this issue, we are developing a support app that simplifies the legal aspects of AI system development, covering the entire lifecycle, from conception to distribution. The current app, which covers the key legal area of copyright and will soon include GDPR and the AI Act, aims to bridge the gap between AI research and agriculture. An evaluation of our app by experts from both the legal and the IT domains shows that the app assists the developers so that they make legally correct statements. Consequently, it promotes legal compliance and awareness among developers, contributing to the seamless integration of AI into agriculture. The need for compliant AI systems in various industries, including agriculture, will only increase as regulations evolve.
The Internet of Things (IoT) is the enabler for new innovations in several domains. It allows the connection of digital services with physical entities in the real world. These entities are devices of different categories and sizes range from large machinery to tiny sensors. In the latter case, devices are typically characterized by limited resources in terms of computational power, available memory and sometimes limited power supply. As a consequence, the use of security algorithms requires of them to work within the limited resources. This means to find a suitable implementation and configuration for a security algorithm, that performs properly on the device, which may become a challenging task. On the other side, there is the desire to protect valuable assets as strong as possible. Usually, security goals are recorded in security policies, but they do not consider resource availability on the involved device and its power consumption while executing security algorithms. This paper presents an IoT security configuration tool that helps the designer of an IoT environment to experiment with the trade-off between maximizing security and extending the lifetime of a resource constrained IoT device. The tool is controlled with high-level description of security goals in the form of policies. It allows the designer to validate various (security) configurations for a single IoT device up to a large sensor network.
Das Interesse am Lehrkonzept des Inverted Classroom (ICM) erfreut sich in den letzten Jahren zunehmender Beliebtheit und mit Beginn der Corona-Pandemie und dem damit verbundenen Umstieg auf Online-gestützt Lehrformate ist es noch einmal deutlich gestiegen. Beim ICM wird die Phase der Wissensvermittlung aus der Präsenzphase der traditionellen Lehrveranstaltung umgedreht: Was bisher während der gemeinsamen Veranstaltungszeit präsentiert wurde, wird nun über Texte, Videos u.a. in eine vorgelagerte Selbstlernphase aus der Veranstaltungszeit ausgelagert. Die gemeinsame Präsenzzeit wird für aktives Lernen, Vertiefung, Diskussion oder andere aktive Formate genutzt. Das Inverted Classroom Modell wird Disziplin- und veranstaltungsübergreifend in der Lehre sowohl in Schulen wie auch Hochschulen genutzt.
Die von Sutherland und Schwaber entwickelte Scrum-Methodik ist ein etabliertes Vorgehensmodell in der Software-Entwicklung und dem Projektmanagement. Scrum bietet durch definierte Rollen, Artefakte und Ereignisse einen Rahmen in dem inkrementell an der Entwicklung eines Produktes gearbeitet werden kann. Diese Inkremente werden in Arbeitszyklen (Sprints) erarbeitet, bei denen die stetige Verbesserung des Produktes und der Arbeitsweise im Fokus stehen. Mit eduScrum oder Scrum4Schools wird Scrum in die Lehre übertragen.
Es liegt auf der Hand, dass sich die Konzepte des ICM und Scrum sehr gut ergänzen und die Scrum Methodik einen formalen Rahmen für ICM bieten kann.
Der Beitrag beschreibt die Umsetzung dieser Kombination agiler Methodiken aus Scrum im Kontext des Inverted Classroom in einer Informatik-Grundlagenveranstaltung an der Hochschule Osnabrück.
Im Modul Algorithmen und Datenstrukturen ist das Inverted Classroom Modell mit der Scrum-Methodik kombiniert. Die Studierenden erarbeiten die Inhalte des Moduls im Lernmanagementsystem mithilfe von Videoaufzeichnungen, digitalem Skript und interaktiven Übungseinheiten. Der Wegfall der klassischen Vorlesung ermöglicht mehr Zeit zur Beantwortung von Fragen, Diskussionen sowie der Reflexion des Erlernten durch Hörsaal-Quizze. Die Themen der Veranstaltung werden vorgegeben, aber die Bearbeitung erfolgt individuell und die Studierenden gestalten ihre eigenen Lernprozesse. Theorie und Praxis der Veranstaltung werden analog zur Scrum-Methodik in mehrwöchigen Sprints im Team bearbeitet. Die Aufgaben sind in den Kontext einer virtuellen Betriebssystemumgebung eingebettet und bauen aufeinander auf. Das Softwareprojekt wird hierzu als GitLab-Repository zur Verfügung gestellt. Die Verwendung von Git und integrierten Test-Routinen entsprechen einer realitätsnahen Vorgehensweise, wie sie in der Softwareentwicklung allgemein gängige Praxis ist.
Oleamide is used as a lubricant in the manufacturing and application of polypropylene (PP) medical devices. Samples of PP were prepared with 0, 1500, and 15 000 ppm oleamide content as lubricant. The samples were either left non-sterile, sterilized with ethylene oxide (ETO), γ-radiation (γ) or autoclaved (A) and stored for up to 4 weeks. To determine the oleamide bulk-to-surface distribution depending on sterilization method and storage time an extraction method and a washing technique were applied. The oleamide content was determined by gas chromatography (GC-FID) and compared with the coefficient of friction (COF). The COF dependent on the measured lubricant content at the surface. The content of lubricant on the surface depends on the type of sterilization: ETO increased the lubricant content to some extent, γ-sterilization and autoclaving reduced it. After storage, no migration of the lubricant to the surface could be detected.
In modern times, closed-loop control systems (CLCSs) play a prominent role in a wide application range, from production machinery via automated vehicles to robots. CLCSs actively manipulate the actual values of a process to match predetermined setpoints, typically in real time and with remarkable precision. However, the development, modeling, tuning, and optimization of CLCSs barely exploit the potential of artificial intelligence (AI). This paper explores novel opportunities and research directions in CLCS engineering, presenting potential designs and methodologies incorporating AI. Combining these opportunities and directions makes it evident that employing AI in developing and implementing CLCSs is indeed feasible. Integrating AI into CLCS development or AI directly within CLCSs can lead to a significant improvement in stakeholder confidence. Integrating AI in CLCSs raises the question: How can AI in CLCSs be trusted so that its promising capabilities can be used safely? One does not trust AI in CLCSs due to its unknowable nature caused by its extensive set of parameters that defy complete testing. Consequently, developers working on AI-based CLCSs must be able to rate the impact of the trainable parameters on the system accurately. By following this path, this paper highlights two key aspects as essential research directions towards safe AI-based CLCSs: (I) the identification and elimination of unproductive layers in artificial neural networks (ANNs) for reducing the number of trainable parameters without influencing the overall outcome, and (II) the utilization of the solution space of an ANN to define the safety-critical scenarios of an AI-based CLCS.
Bamboo is an environmentally friendly alternative to conventional materials in mechanical engineering such as steel or aluminium. Bamboo is the fastest growing plant in the world. Instead of releasing CO2 during the manufacturing process, bamboo absorbs CO2 as it grows.
In addition to the sustainability aspect, bamboo tubes also offer excellent properties as a lightweight construction material, which have been optimised through evolution. Bamboo tubes have high strength and stiffness at low weight when used as tension-compression bars or bending beams. Bamboo has strong, high-density fibres at the boundary area, where bending stresses are greatest. Towards the inside, where the stresses are lower, the bamboo becomes porous to optimise weight. This, together with knots arranged in regular intervals, counteracts buckling.
In mobile applications such as cars and bicycles, lightweight construction is sought for energy efficiency reasons. Because of its excellent lightweight properties, the project investigated whether bamboo could be used in mobile, automotive or agricultural engineering. For example, a bamboo bicycle frame has been developed with the aim to be as light as possible. There are bamboo bicycles on the market, but they can only be made one at a time by hand. The bamboo tubes are joined together and functional elements such as the bottom bracket and headset are integrated by wrapping them in resin-impregnated natural or carbon fibres. This makes the joints very heavy. A different approach is taken here: the bamboo tubes are drilled out slightly to achieve a defined internal diameter, and then short aluminium tubes are glued into the bamboo canes from the inside. To prevent the cane from breaking in the circumferential direction, i.e. perpendicular to the fibre direction, the bamboo tubes are wrapped in a thin layer of natural or carbon fibre impregnated with synthetic resin. The aluminium tubes and functional elements are welded or soldered together beforehand.
The design of the bicycle frame, i.e. the dimensioning of the bamboo tubes and joints, was based on extensive bending and tensile tests to determine the strength properties of the natural material bamboo. The bonding between the bamboo cane and the aluminium tube was also investigated experimentally. Finally, several prototype bicycle frames were made and tested for durability according to DIN-EN-14764. The frames passed the tests.
The result is a bamboo bicycle that is manufactured with standardised connectors and joints. The assembly concept developed allows both fully automated and semi-automated series production of bamboo bicycles.
The energy transition involves various challenges. One key aspect is the decentralization of power generation, which requires new actors. In order to integrate these into the system in the best possible way, there are various approaches e.g. in cooperation in citizens' initiatives or cooperatives (Dorniok, 2016).
Cooperation in general can enable the implementation of certain business models or can increase profitability by the exploitation of economies of scale (Skovsgaard & Jacobsen, 2017; Theurl, 2010). Synergy effects result from the utilization of know-how, different technologies or resources of the partners involved to complement the own competencies and services (Eggers & Engelbrecht, 2005; Sander, 2009). Cooperation exists in various industries and enable the participating companies to compensate their size-related resource deficits (Glaister & Buckley, 1996; Todeva & Knoke, 2005). This creates the opportunity to develop innovations, open up new markets, exploit newly created economies of scale and share costs and risks (Franco & Haase, 2015). In agriculture, cooperation in the form of cooperatives have been of essential importance for a long time, especially with the aim of exploiting synergy effects (Bareille et al., 2017). In the field of renewable energy development, cooperation in form of citizen cooperatives make a significant contribution to the participation of citizens in political, social and financial aspects of the energy transition (Huybrechts & Mertens, 2014). Energy cooperatives are frequently discussed as a potential actor in the energy transition and are increasingly being established to advance the common interests of stakeholders. For example, the joint operation of decentralized power generation plants can involve new actors in the energy transition through regional cooperation (Walk, 2014).
Existing biogas plants in Germany need new business models after the 20-year Renewable Energy Sources Act feed-in tariff expires. For continued operation, a business model innovation is needed, which can be realized based on the different technical utilization pathways. Cooperation can have a significant impact on the profitability of the different business models, especially by exploiting synergy effects (Karlsson et al., 2019). In addition, cooperation can help to ensure that existing plants continue to operate at all.
Currently, the most widespread use of biogas in Germany is in the coupled generation of electricity and heat. Additionally, there is the possibility of upgrading biogas to biomethane or biogenic hydrogen path (Mertins & Wawer, 2022).
Different options for cooperative business models that exist in the biogas utilization pathways are presented. The focus is on explaining the advantages of a joint approach compared to single-farm business models and identifying the relevant actors. Subsequently, drivers and barriers for the different cooperative business models are identified and classified based on 20 semi-structured interviews with plant operators in the administrative district of Osnabrück. The aim is to identify drivers and barriers for cooperative post-EEG operation. As a result, political instruments are to be found that make it possible to involve relevant actors and thus stimulate the best possible continued operation from the point of view of the energy system. The results are structured according to the PESTEL analysis. This assigns drivers and barriers to the categories political, economic, sociocultural, technological, ecological and legal (Kaufmann, 2021). The analysis of the interviews is supplemented and validated by a literature review.
Drivers and barriers for cooperative business models are manifold and can vary mainly depending on the plant and the operator.
Drivers
• Political
o Promotion of renewable energies: reduce dependence on fossil (Russian) fuels
• Economic
o Expectation of synergies (information sharing, shared risk, economies of scale)
o Planning security (fixed supply or purchase contracts)
o Access to new markets (not accessible by single-farm business models)
o Cost savings by sharing infrastructure, technology
o Positive return expectation
• Sociocultural
o Motivating, innovative environment
o Lowers barriers to participation in new markets
o Target-oriented partnerships
o Better use of capacities and strengths
o Strengthening regional value creation
• Technological
o Economies of scale (efficiency)
o Available, mature technology
o Storable, transportable gas
o Well-developed infrastructure
• Ecological
o Increase in plant efficiency
o Reduction of greenhouse gas emissions
o Promotion of the circular economy by utilization of organic waste and agricultural residues
o Improving soil quality (fermentation residues as fertilizer)
Barriers
• Political
o Competition to other renewable energies
• Economic
o Uncertainty about future development of energy markets
o Disagreements between the cooperation partners
o Lack of flexibility due to longer-term contractual obligations
o Allocation of profits
• Sociocultural
o Cooperation with current competitor
o Cultural differences and lack of trust
o Acceptance by the general public (e.g. overproduction of maize)
• Technological
o Different technology that is difficult to combine
o Data protection
• Ecological
o Competition for agricultural land
o Use of monocultures
o Emissions from plant
o Pollution from transport
• Legal
o Legal requirements and regulations
o Unfavorable regulatory environment, e.g. long permitting process
One finding is that uncertainty is a major barrier for plant operators. This includes uncertainty about regulatory frameworks and political requirements, as well as about the general development of the energy markets. In addition, social factors such as lack of reliability and disagreement about revenue sharing are a potential barrier. A key driver for the implementation of cooperative business models is the expectation of synergy effects. In addition, operators are driven by a positive expectation of returns and the responsibility for securing the energy supply in times of crisis.
The drivers identified can now be used to develop strategies to advance cooperative business models. In particular, synergy effects should be exploited so that operators can benefit from cooperation. The advantages can also be highlighted and communicated to increase acceptance among the general public. Another important step is to reduce the barriers discussed above. In order to reduce social barriers in particular, it may be advisable to include an external partner in the cooperation, such as a municipal utility that operates an upgrading plant and concludes purchase agreements with the individual partners. In addition, it would be politically expedient to provide the operators with a clear framework for the future in order to reduce uncertainties. As a further aspect, knowledge transfer on new technologies and markets should take place.
Currently, soil nutrient analysis involves two separate processes for soil sampling and nutrient analysis: 1. field soil sampling and 2. laboratory analysis. These two - separate - main work processes are combined and conceptualised for a mobile field laboratory so that soil sampling and analysis can be carried out simultaneously in the field. The module-based field laboratory "soil2data" can carry out these two main work processes in parallel and consists of 5 different task-specific modules that build on each other: app2field, field2soil, app2liquid, liquid2data and data2app. The individual modules were designed and built for the sub-process steps and adapted to the special features of the mobile field laboratory "soil2data". The biggest advantage is that the analysis results are available immediately, and a fertiliser recommendation can be generated instantly. For further analyses, the results are stored in the data cloud. The soil material remains in the field. In the ongoing project "Prototypes4soil2data", the mobile field laboratory soil2data is being further developed into a prototype with a modular structure.
While developing traffic-based cognitive enhancement technology (CET), such as bike accident prevention systems, it can be challenging to test and evaluate them properly. After all, the real-world scenario could endanger the subjects’ health and safety. Therefore, a simulator is needed, preferably one that is realistic yet low cost. This paper introduces a way to use the video game Grand Theft Auto V (GTA V) and its sophisticated traffic system as a base to create such a simulator, allowing for the safe and realistic testing of dangerous traffic situations involving cyclists, cars, and trucks. The open world of GTA V, which can be explored on foot and via various vehicles, serves as an immersive stand-in for the real world. Custom modification scripts of the game give the researchers control over the experiment scenario and the output data to be evaluated. An off-the-shelf bicycle equipped with three sensors serves as a realistic input device for the subject’s movement direction and speed. The simulator was used to test two early-stage CET concepts enabling cyclists to sense dangerous traffic situations, such as trucks approaching from behind the cyclist. Thus, this paper also presents the user evaluation of the cycling simulator and the CET used by the subjects to sense dangerous traffic situations. With the knowledge of the first iteration of the user-centered design (UCD) process, this paper concludes by naming improvements for the cycling simulator and discussing further research directions for CET that enable users to sense dangerous situations better.
Knowledge of the small-scale nutrient status of a field is an important basis for decision-making when it comes to optimising the fertiliser use in crop production. Currently, the traditional method involves soil sampling in the field and soil sample analysis in the laboratory as two separate working processes.
The previous research project "soil2data" developed a mobile field laboratory for different carrier vehicles. In the follow-up project "prototypes4soil2data", the results of soil2data are further developed. A mixed soil sample is collected during the drive on the field. The soil sample is then wet-chemically prepared and analysed. The overall soil sampling and analysis process is divided into the following process steps: soil sampling planning, soil sampling, soil preparation, soil analysis and data management. The process steps are modified for the mobile field laboratory and the process steps run in parallel. The new soil extraction method is based on official German methods (VDLUFA) to ensure the interoperability of the analysis results with the VDLUFA fertiliser recommendations. An innovative key component is the NUTRISTAT analysis module (lab-on-chip with ISFET measurement technology). It can measure pH, the nutrients NO3-, H2PO4-, K+ and the electrical conductivity. In addition to the advantages of rapid data availability and no need to transport soil material to the laboratory, it provides a future basis for new application, e.g. verification of current results in the field during soil sampling with existing results or dynamic adjustment of soil sampling during work in the field.
Innerhalb eines Forschungsprojektes wurde ein Energiesystemoptimierungsmodell entwickelt, das mögliche Geschäftsmodelle als Weiterbetriebsoptionen für Biogasanlagen betrachtet. Insbesondere der Einfluss von fluktuierenden Strommarktpreisen und variierenden Treibhausgasquoten soll kritisch im innerdeutschen Kontext beleuchtet werden.
Aufgrund der Folgen des Klimawandels bekommen klimaanpassende Maßnahmen immer mehr Bedeutung. Durch versiegelte Flächen und Starkregen können einerseits Überschwemmungen entstehen, anderseits führen Hitze und wenig Niederschlag zu Trockenheit und Wassermangel. Deswegen ist es wichtig, klimaanpassende Maßnahmen zu fördern und diese den Bürgern näher zu bringen.
Das Ziel dieser Bachelorarbeit ist, eine Webanwendung zu entwickeln, die die Bürger zur Nutzung von Regenwasser und zu Entsiegelungen als klimaanpassende Maßnahmen motiviert, indem Nutzern eine individuelle Berechnung der Kosten und des Nutzens angeboten wird. Dafür folgt die Entwicklung der Webanwendung dem menschzentrierten Gestaltungsprozess, um eine hohe Benutzerfreundlichkeit zu erreichen. Es werden Usability-Tests als Evaluation durchgeführt.
Die Ergebnisse der Evaluation zeigen, dass die entwickelte Webanwendung die Nutzer zufriedenstellt und die Anforderungen erfüllt. Der menschzentrierte Gestaltungsprozess ist für das betrachtete Themenfeld ein wirksames und zielführendes Vorgehen bei der Entwicklung interaktiver Systeme.
Nach dem Auslaufen der 20-jährigen Förderung über eine Einspeisevergütung im Rahmen des Erneuerbare-Energien-Gesetzes (EEG) gibt es für deutsche Biogasanlagen diverse technische Möglichkeiten für einen Weiterbetrieb. Neben der Wirtschaftlichkeit sind die Anlagenbetreibenden ein wesentlicher Entscheidungsfaktor für den Weiterbetrieb der Anlage. Somit ergibt sich die zentrale Fragestellung „Welche Treiber und Hemmnisse für Betreibende von Bestandsbiogasanlagen in Deutschland bestehen in den verschiedenen Nutzungspfaden für Biogas, sowie für kooperative Geschäftsmodelle?“. Die Erkenntnisse können unter anderem dafür genutzt werden, die Situation der Anlagenbetreibenden besser zu verstehen, um notwendige Unterstützung für einen Weiterbetrieb, beispielsweise durch Kommunen, zur Verfügung stellen zu können.
Wie können wir die Lehre heute gestalten, wenn wir nicht wissen, was morgen gebraucht wird?
Unter dieser Perspektive werden aktuelle Herausforderungen und Chancen universitärer Bildung betrachtet. Ausgehend von einer höheren organisatorischen Perspektive übergehend zu der Mikroperspektive einer einzelnen Lehrveranstaltung. Die Rolle von generativen KI-Systemen wird betrachtet.
Der Begriff New Learning im Kontext von New Work wird aufgegriffen und in Anlehnung an das Agile Manifesto der SW-Entwicklung wird ein agiles Manifest für die Lehre formuliert. Dieses wird in den Zusammenhang mit den sog. Zukunftskompetenzen oder Future Skills gebracht.
Der Beitrag beschreibt das Veranstaltungskonzept ICMScrum, welches die Ideen des Inverted Classroom mit Elementen aus Scrum kombiniert. Beginnend mit Anforderungen des aktuellen und zukünftigen Arbeitsmarktes werden die zentralen Elemente der Methodik anhand eines praktizierten Beispiels vorgestellt und kritisch diskutiert.
The expiry of national subsidies for biogas in Germany means that new business models are needed. Furthermore, hydrogen is expected to make a significant contribution to the energy transition in the future. Therefore, potentials for the production of hydrogen from biogas are identified in this study. A joint upgrading infrastructure is developed that models the collaborative upgrading of biogas to hydrogen for existing biogas plants with subsequent gas grid injection. Furthermore, regions are identified that are particularly suitable as pioneer regions in Germany due to a high potential for green hydrogen production and comparatively low costs for hydrogen production. The modeling shows that collaborative upgrading achieves significant cost savings compared to single-farm upgrading. Furthermore, the potential for hydrogen production from biogas and the costs of upgrading differ significantly within the administrative districts in Germany.
Today's development of client-side web applications is based on one of the JavaScript-frameworks, such as Angular or React. The excessive dependencies that arise in the ecosystem from the Node-Package-Manager increase the security risk and the dependency of your own web application on third-party packages. Moreover, the frameworkless approach proposes a renaissance of classic web development, because it strives to avoid external dependencies as far as possible and to fall back on the standards. Whether the implementation achieves maintainability and security of frameworks is questionable. Therefore, it makes sense to research which core concepts of the frameworks meet the requirements for maintainability and security and how these are implemented. The novelty is that the concepts to be explored are moved to a standard in order to ensure the developer efficiency, security, performance and maintainability in the long term. This allows existing approaches to focus on other essential features.
The Internet of Things (IoT) is the enabler for new innovations in several domains. It allows the connection of digital services with real, physical entities. These entities are devices of different categories and range in size from large machinery to tiny sensors. In the latter case, devices are typically characterized by limited resources in terms of computational power, available memory and sometimes limited power supply. As a consequence, the use of security algorithms requires expert knowledge in order for them to work within the limited resources. That means to find a suitable configuration for the algorithms to perform properly on the device. On the other side, there is the desire to protect valuable assets as strong as possible. Usually, security goals are captured in security policies, but they do not consider resource availability on the involved device and their consumption while executing security algorithms. This paper presents a resource aware information exchange model and a generation tool that uses high-level security policies as input. The model forms the conceptual basis for an automated security configuration recommendation system.
Power consumption has become a major design constraint, especially for battery-powered embedded systems. However, the impact of software applications is typically considered in later phases, where both software and hardware parts are close to their finalization. Power-related issues must be detected in early stages to keep the development costs low, satisfy time-to-market, and avoid cost-intensive redesign loops. Moreover, the variety of hardware components, architectures, and communication interfaces make the development of embedded software more challenging. To manage the complexity of software applications, approaches such as model-driven development (MDD) may be used. This article proposes a power-estimation approach in MDD for software application models in early development phases. A unified modeling language (UML) profile is introduced to model power-related properties of hardware components. To determine the impact of software applications, we defined two analysis methods using simulation data and a novel in-the-loop concept. Both methods may be applied at different development stages to determine an energy trace, describing the energy-related behavior of the system. A novel definition of energy bugs is provided to describe power-related misbehavior. We apply our approach to a sensor node example, demonstrate an energy bug detection, and compare the runtime and accuracy of the analysis methods.
Reibermüdung ist ein Phänomen, welches an den Kontakträndern von in Berührung ste-henden, kraftübertragenden Bauteilen beobachtet werden kann. Typische Maschinenele-mente, die in diesem Mode versagen können, sind z. B. die Schwalbenschwanzverbindung sowie ihre Ableger, die mehrzahnigen Tannenbaumfixierungen. In der Literatur beschrie-bene Untersuchungen weisen für Flachproben mit Reibbrücken ein Lebensdauerverhalten mit einem lokalen Minimum über der Anpresskraft der Reibbrücken aus. Die vorliegende Arbeit untersucht mithilfe des Sines-Ermüdungskriteriums, kombiniert mit Grenzwerten gemäß FKM-Richtlinie, ob ein solches Verhalten auch für die Schwalbenschwanzverbin-dung zutrifft. Im Gegensatz zur Reibbrückenanordnung mit separater Einleitung von kon-stanter Pressung und Längslastamplitude fluktuieren bei der Schwalbenschwanzverbin-dung die Anpresskraft und Zugkraft mit der einzigen am Hals eingeleiteten Last.
In this experimental work, the quasi static and fatigue properties of a 40 wt.% long carbon fiber reinforced partially aromatic polyamide (Grivory GCL-4H) were investigated. For this purpose, microstructural parameter variations in the form of different thicknesses and different removal directions from injectionmolded plates were evaluated. Mechanical properties decreased by increasing misalignment away from the melt flow direction. By changing the specimen thickness, no change in the general fiber distribution pattern transversal and normal to the axis of melt flow was observed. It has shown that with increasing specimen thickness the quasi static properties along the melt flow direction decreased and vice versa resulting in superior properties normal to the melt flow axis. At around 5 mm, an intersection suggests quasi-isotropic behavior. In addition, the fatigue strength of the material was significantly higher in the flow direction than normal to the flow direction. No change in fatigue life was observed while changing specimen thickness. The Basquin equation seems to describe the effect of stress amplitude on the fatigue strength of this composite. Scanning electron microscopy was used to investigate fracture surfaces of tested specimens. Results show that mechanical properties and morphological structures depend highly on fiber orientation.
Der nachfolgende Projektbericht, welcher im Rahmen des Masterprojektes und des Moduls „Bildgebende Sensortechnik“ erarbeitet wurde, ist wie folgt den beiden Fächern zuzuordnen.
Die Kapitel, welche sich mit der Inbetriebnahme und den Umgang des SICK RMS320 Radarsensors beschäftigen, sind Teil des Masterprojektes. Dies betrifft die Kapitel 2.2, 4.1, 4.3 und in Teilen das Kapitel 4.5.
Dem Modul „Bildgebende Sensortechnik“ sind hingegen die Messung des Einflusses von Kleidung auf die Erkennungsfähigkeit eines Menschen sowie die Radarmessungen der verschiedene Prüfkörper zuzuordnen. Dies wird in den Kapiteln 2.3, 3, 4.2, 4.4 und 4.5 behandelt.
Die „Grundlagen der Radartechnik“ sind für beide Teile gleichbedeutend wichtig.
The simulation of the residual stress field achieved by shot peening cannot be carried out on component-large models. Hence, an efficient unit cell model for the simulation of the shot peening process is developed. The model allows both, the simple inclusion of a pre-stress and the evaluation of the up-arching of the Almen strip. For this purpose, generalized coupling constraints for the periodic boundaries of the unit cell are developed. These allow for displacement and rotation of the coupled boundaries relative to each other. In the coupling constraints, this is accomplished by respective variables, which can either be prescribed to the analysis or read out as a result from the analysis. Hence, the unit cell can expand, shear, bend and twist under driving forces like, e. g., residual stresses or thermal effects. At the same time, deformations of the cell’s periodic boundary pairs are kept congruent by the generalized coupling. The ability to cover expansion is novel regarding known periodic boundary conditions. Also, the application of a generalized unit cell to shot peening is new.
Results obtained with the generalized unit cell are displayed, demonstrating its capabilities: A fundamental analysis of the residual stress field from shot peening shows inhomogeneities at a fatigue relevant level to be inevitable. A validation of the model was done by comparison with experimental Almen strip shot peening tests reported in literature. Shot peening under pre-stress is demonstrated and its results in terms of residual stress are evaluated. The application of the generalized unit cell is not limited to shot peening.
Kugelstrahlen ist ein im Maschinenbau eingesetztes Verfahren zur Steigerung der Ermüdungsfestigkeit. Es wird z. B. bei hochbelasteten Komponenten in der Luft- und Raumfahrt, der Fahrzeugtechnik, im Turbomaschinenbau und weiteren Industriezweigen angewandt. Die Einstellung der Betriebsparameter der Kugelstrahlanalage findet üblicherweise mit kostenintensiven empirischen Versuchen statt, mit dem Ziel, die vorgegebene Druckeigenspannung zu erreichen. In [1, 2] wird auf der Basis einer dort beschriebenen neuartigen Elementarzelle vorgeschlagen, die Almenstreifenaufbiegung als Mittel zur Spezifikation der Verfestigung heranzuziehen. Dazu ist deren Simulation notwendig, welche sich mit der entwickelten Elementarzelle wirtschaftlich bewerkstelligen lässt. In der hier vorliegenden Veröffentlichung werden die der Elementarzelle zugrundeliegenden Finite-Elemente-Netze (FE-Netze) mithilfe von Einzelbe-schussversuchen validiert. Weiterhin wird eine ähnlichkeitsmechanische Betrachtung des Kugelstrahlprozesses zur vereinfachten Parametereinstellung vorgestellt.
Process modeling languages help to define and execute processes and workflows. The Business Process Model and Notation (BPMN) 2.0 is used for business processes in commercial areas such as banks, shops, production and supply industry. Due to its flexible notation, BPMN is increasingly being used in non-traditional business process domains like Internet of Things (IoT) and agriculture. However, BPMN does not fit well to scenarios taking place in environments featuring limited, delayed, intermittent or broken connectivity. Communication just exists for BPMN - characteristics of message transfers, their priorities and connectivity parameters are not part of the model. No backup mechanism for communication issues exists, resulting in error-prone and failing processes. This paper introduces resilient BPMN (rBPMN), a valid BPMN extension for process modeling in unreliable communication environments. The meta model addition of opportunistic message flows with Quality of Service (QoS) parameters and connectivity characteristics allows to verify and enhance process robustness at design time. Modeling of explicit or implicit, decision-based alternatives ensures optimal process operation even when connectivity issues occur. In case of no connectivity, locally moved functionality guarantees stable process operation. Evaluation using an agricultural slurry application showed significant robustness enhancements and prevented process failures due to communication issues.
Simulation von Laserscannern in Pflanzenbeständen für die Entwicklung umfeldbasierter Funktionen
(2018)
Es werden drei Modellierungsansätze zur Simulation von Laserscannern in Pflanzenbeständen für die Entwicklung umfeldbasierter Fahrzeugfunktionen beschrieben. Das Sensorsignal der Distanzmessung wird dabei anhand realer Messwerte oder phänomenologisch und auf der Basis empirisch ermittelter Kennwerte in Abhängigkeit von objekt- und sensorspezifischen Einflussfaktoren abgebildet. Basierend auf den Methoden zur Simulation von Distanzmesssystemen der Open Source Simulationsumgebung Gazebo wurden die Modellierungsansätze als spezifische Sensor- und Umfeldmodelle implementiert. Die Modelle wurden insbesondere für den Einsatz an mobilen landwirtschaftlichen Arbeitsmaschinen und für die Anwendung in der Getreideernte optimiert.
This paper describes the development and test of a novel LiDAR based combine harvester steering system using a harvest scenario and sensor point cloud simulation together with an established simulation toolchain for embedded software development. For a realistic sensor behavior simulation, considering the harvesting environment and the sensor mounting position, a phenomenological approach was chosen to build a multilayer LiDAR model at system level in Gazebo and ROS. A software-in-the-loop simulation of the mechatronic steering system was assembled by interfacing the commercial AppBase framework for point cloud processing and feature detection algorithms together with a machine model and control functions implemented in MATLAB/ Simulink. A test of ECUs in a hardware-in-the-loop simulation and as well as HMI elements in a driver-in-the-loop simulation was achieved by using CAN hardware interfaces and a CANoe based restbus simulation.
This article proposes the concept of a simulation framework for environmental sensors with multilevel abstraction in agricultural scenarios. The implementation case study is a simulation of a grain-harvesting scenario enabled by LiDAR sensors. Environmental sensor models as well as kinematics and dynamic behavior of machines are based on the robotics simulator Gazebo. Models for powertrain, machine process aggregates and peripheral simulation components are implemented with the help of MATLAB/ Simulink and with the robotics middleware Robot Operating System (ROS). This article deals with the general concept of a multilevel simulation framework and in particular with sensor and environmental modeling.
This paper presents an optimized algorithm for estimating static and dynamic gait parameters. We use a marker- and contact-less motion capture system that identifies 20 joints of a person walking along a corridor.
Based on the proposed gait cycle detection basic metrics as walking frequency, step/stride length, and support phases are estimated automatically. Applying a rigid body model, we are capable to calculate static and dynamic gait stability metrics. We conclude with initial results of a clinical study evaluating orthopaedic technical support.
In der Schriftenreihe „Voneinander Lehren lernen“, die vom LearningCenter der Hochschule Osnabrück herausgegeben wird, werden anwendungsbezogene Beiträge zur Qualitätsentwicklung in Studium und Lehre publiziert.
Die Schriftenreihe ist an das hochschuldidaktische Konzept des „Scholarship of Teaching and Learning“ angelehnt. Demnach soll sie insbesondere den Fachlehrenden aller Studiengänge als Plattform dienen, um ihre eigenen Erfahrungen, Ideen und Konzepte zur Lehr- und Studiengangentwicklung systematisch zu reflektieren und entsprechende Erkenntnisse für andere nutzbar zu machen. Ziel ist es, den Diskurs über hochschuldidaktische Themen in die Fächer zu tragen und so nachhaltig zu einer hohen Qualität der Lehr-Lernprozesse in den Studiengängen beizutragen. Ergänzt werden die Texte der Fachlehrenden um Beiträge von Mitarbeiter*innen der im Bereich Studium und Lehre tätigen Organisationseinheiten.
Die Schriftenreihe ist eng an das Lehrkolleg der Hochschule Osnabrück gekoppelt. Dabei handelt es sich um ein Angebotsformat des LearningCenters, in dem Professor*innen und Lehrkräfte für besondere Aufgaben die Möglichkeit haben, unter hochschuldidaktischer Begleitung innovative Lehrentwicklungsprojekte in ihren eigenen Lehrveranstaltungen und Modulen umzusetzen. Der erste Band der Schriftenreihe enthält Beiträge von Teilnehmer*innen des Lehrkollegs 2018, in dem verschiedene Entwicklungsprojekte zur Förderung von Kompetenzen für selbstreguliertes Lernen durchgeführt wurden.
We describe an automated approach, to easily track patients regaining their walking ability while recovering from neurological diseases like e.g. stroke. Based on captured gait data and objective measures derived out of it the rehabilitation process can be optimized and thus steered. In order to apply such system in clinical practice two key requirements have to be fulfilled: (i) the system needs to be applicable in terms of ease of use and performance; (ii) the derived measures need to be accurate.
The Internet of Things (IoT) relies on sensor devices to measure real-world phenomena in order to provide IoT services. The sensor readings are shared with multiple entities, such as IoT services, other IoT devices or other third parties. The collected data may be sensitive and include personal information. To protect the privacy of the users, the data needs to be protected through an encryption algorithm. For sharing cryptographic cipher-texts with a group of users Attribute-Based Encryption (ABE) is well suited, as it does not require to create group keys. However, the creation of ABE cipher-texts is slow when executed on resource constraint devices, such as IoT sensors. In this paper, we present a modification of an ABE scheme, which not only allows to encrypt data efficiently using ABE, but also reduces the size of the cipher-text, that must be transmitted by the sensor. We also show how our modification can be used to realise an instantaneous key revocation mechanism.
he development of context-aware applications is a difficult and error-prone task. The dynamics of the environmental context combined with the complexity of the applications poses a vast number of possibilities for mistakes during the creation of new applications. Therefore it is important to test applications before they are deployed in a life system. For this reason, this paper proposes a testing tool, which will allow for automatic generation of various test cases from application description documents. Semantic annotations are used to create specific test data for context-aware applications. A test case reduction methodology based on test case diversity investigations ensures scalability of the proposed automated testing approach.
Smart city applications in the Big Data era require not only techniques dedicated to dynamicity handling, but also the ability to take into account contextual information, user preferences and requirements, and real-time events to provide optimal solutions and automatic configuration for the end user. In this paper, we present a specific functionality in the design and implementation of a declarative decision support component that exploits contextual information, user preferences and requirements to automatically provide optimal configurations of smart city applications. The key property of user-centricity of our approach is achieved by enabling users to declaratively specify constraints and preferences on the solutions provided by the smart city application through the Decision Support component, and automatically map these constraints and preferences to provide optimal responses targeting user needs. We showcase the effectiveness and flexibility of our solution in two real usecase scenarios: a multimodal travel planner and a mobile parking application. All the components and algorithms described in this paper have been defined and implemented as part of the Smart City Framework CityPulse.
Reliable information processing is an indispensable task in Smart City environments. Heterogeneous sensor infrastructures of individual information providers and data portal vendors tend to offer a hardly revisable information quality. This paper proposes a correlation model-based monitoring approach to evaluate the plausibility of smart city data sources. The model is based on spatial, temporal, and domain dependent correlations between individual data sources. A set of freely available datasets is used to evaluate the monitoring component and show the challenges of different spatial and temporal resolutions.
Interpolation of data in smart city architectures is an eminent task for the provision of reliable services. Furthermore, it is a key functionality for information validation between spatiotemporally related sensors. Nevertheless, many existing projects use a simplified geospatial model that does not take the infrastructure, which affects events and effects in the real world, into account. There are various available algorithms for interpolation and the calculation of routes on infrastructure based graphs and distances on geospatial data. This work proposes a combined approach by interconnecting detailed geospatial data whilst regarding the underlying infrastructure model.
Pregnancy loss is the most common complication in pregnancy. Yet those who experience it can find it challenging to disclose this loss and feelings associated
with it, and to seek support for psychological and physical recovery. We describe our process for
interleaving interviews, theoretical development, speculative design, and prototyping Not Alone to
explore the design space for online disclosures and
support seeking in the pregnancy loss context.
Interviews with 27 women who had experienced pregnancy loss resulted in theoretical concepts such as
“network-level reciprocal disclosure” (NLRD). We discuss how interview findings informed the design of
the Not Alone prototype, a mobile application aimed at enabling disclosure and social support exchange among those with pregnancy loss experience. The Not Alone prototype embodies concepts that facilitate NLRD: perceptions of homophily, anonymity levels, and selfdisclosure by talking about one’s experience and engaging with others’ disclosures. In future work, we will use Not Alone as a technology probe for exploring
NLRD as a design principle.
Der Einsatz des ISOBUS zeigt, dass Bedarf an Datenkommunikation auch auf landtechnischen Gespannen besteht. Jedoch wird auch deutlich, dass der ISOBUS mit seiner relativ geringen Datenrate keine Ressourcenreserven für neue Anwendungen aufweist. Aus diesem Grund ist der Wechsel der Übertragungstechnologie für die Weiterentwicklung des ISOBUS zu einem High-Speed ISOBUS notwendig. Eine geeignete und im weiteren Verlauf näher betrachtete Technologie für den Wechsel ist Ethernet. Es wird gezeigt welche Potenziale für den ISOBUS durch Ethernet entstehen und welche Herausforderungen dabei bewältigt werden müssen.
Protection and privacy of data in cooperative agricultural processes : the challenges of the future
(2016)
In agriculture, the growing usage of sensors, smart mobile machinery and information systems results in high volumes of data. The data differs in accuracy, frequency, volume, type and, most importantly, owner of the information. However, cooperative processes and big data analyses require access to comprehensive amounts of data for successful agricultural operation and reasoning. In some processes instructed contractors even gather data belonging to other owners and use it for machinery operation optimisation and accounting (e.g. yield in maize harvest). Today’s approach of data handling has a high potential to conflict with European and national regulations for data protection and privacy. This article presents a concept for continuous data protection and privacy in cooperative agricultural processes. The concept aims at ensuring data sovereignty for the owner while making as much data usable for process operation and big data research at the same time. Briefly explained, owners pick a collection of data and create usage licenses for other players. The licenses specify time-limited and / or position-bound access to the data collection. Privacy environments in soft- and / or hardware protect access rights on end user devices, data share hubs and machinery devices such as agricultural terminals. In addition to access right configurations, digital signatures prevent data manipulation when cooperative players capture data during processes. Socalled signature boxes represent certificated soft- or hardware components, which are located close at data sources (e.g. as hardware attached to sensors on mobile machinery) and bind the data captured with digital signatures.
For Delay-Tolerant Networks (DTNs) many routing algorithms have been suggested. However, their performance depends heavily on the applied scenario. Especially heterogeneous scenarios featuring known and unknown node movements as well as different kinds of data lead to either poor delivery ratios or exhausted network resources.
To overcome these problems this paper introduces Data-Driven Routing for DTNs. Data is categorized according to its requirements into priority queues. Each queue applies an appropriate DTN routing algorithm that fits the data requirements best. Simulation results show that Data-Driven Routing allows high delivery ratios for time-critical data while saving network resources during the transfer of less time-critical data at the same time.
Management of agricultural processes is often troubled by disconnections and data transfer failures. Limited cellular network coverage may prevent information exchange between mobile process participants.
The research projects KOMOBAR and ISOCom designed, implemented und field-tested a delay tolerant platform for robust communication in rural areas and challenging environments. An adaptable combination of infrastructure-based cellular networks and infrastructure-free multihop ad hoc communication (WLAN) leads to a variety of new communication opportunities. Temporal storage and forwarding of data on mobile farm machinery as well as dynamic platform configurations during process runtime strongly enhance reliability and robustness of data transfers.
High Performance and Privacy for Distributed Energy Management: Introducing PrivADE+ and PPPM
(2018)
Distributed Energy Management (DEM) will play a vital role in future smart grids. An important and often
overlooked factor in this concept is privacy. This paper presents two privacy-preserving DEM algorithms
called PrivADE+ and PPPM. PrivADE+ uses a round-based energy management procedure for switchable and
dynamically adaptable loads. PPPM utilises on the market-based PowerMatcher approach. Both algorithms
apply homomorphic encryption to privately gather aggregated data and exchange commands. Simulations
show that PrivADE+ and PPPM achieve good energy management quality with low communication requirements
and without negative influences on robustness.
Ein modulares Framework zur Modellierung, Konfiguration und Regelung von kooperativen Agrarprozessen
(2016)
Die Komplexität vieler Agrarprozesse nimmt aufgrund von technischem Fortschritt, steigenden rechtlichen Anforderungen und Nachweispflichten beständig zu. Prozessketten werden in Kooperation verschiedener Akteure (Landwirt, Lohnunternehmer, Dienstleister, digitaler Vermittler, Behörde) gemeinsam bearbeitet, dokumentiert und geprüft. Ein ökonomisch und ökologisch ressourceneffizientes Management der Prozessausführung stellt eine Herausforderung für alle Akteure dar. Dynamische Prozessveränderungen führen vielfach zu manuellen Eingriffen in die Prozessregelung, die kostenintensive Verzögerungen verursachen. Das Forschungsvorhaben OPeRAte entwirft und evaluiert neu gestaltete Konzepte und Mechanismen zur durchgehenden Organisation und Regelung kooperativer Agrarprozesse. Es werden konfigurierbare und wiederverwendbare Module identifiziert, die sich an Prozessparameter anpassen und in artverwandten Prozessen erneut verwenden lassen. Das OPeRAte-Framework ermöglicht die Zusammenführung aller beteiligten Akteure und Ressourcen (Maschinen, Sensoren, Aktoren, Endgeräte, Server, Daten, etc.) über offene Schnittstellen. Prozessinhaber sollen durch autonome Prozesskonfigurationen und -adaptionen entlastet und durch Visualisierungen zu effizienten Entscheidungen befähigt werden. Die Konzepte dieses Beitrags dienen als Diskussionsgrundlage zur Formulierung von flexiblen und erweiterbaren Lösungsstrategien für die Landtechnik.
Die Nutzung von Sensorsystemen bei der teilflächenspezifischen Bewirtschaftung eines Schlags steigert den Ertrag sowie die Wirtschaftlichkeit des Pflanzenanbaus. Dennoch tragen weitere Faktoren zur optimalen Nährstoffversorgung einer Pflanze bei, als sie von solch einem lokal arbeitenden System erfasst werden. Um die Effizienz dieser Precision Farming Systeme auszubauen ist der nächste, hier erfolgreich durchgeführte Schritt die Anbindung der mobilen Landmaschine über das Internet an eine regionsübergreifende Datenanalyseplattform und die Ausführung zeitkritischer Optimierungsfunktionen auf der Landmaschine.