openHSU – Research Showcase

4485
Research outputs
779
People
140
Organizational Units
108
Projects
31
Conferences
17
Journals
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  • Publication
    Metadata only
    Deep Fading in a Reverberation Chamber for Wireless Device Testing
    Reverberation chambers (RCs) are a feasible option as test environment for evaluation of wireless devices with integrated antenna as they inherently emulate a Rayleigh fading channel. In this paper the dependency of deep fading on the frequency and position/orientation of an equipment under test (EUT) antenna is evaluated for different numbers of RC steps and loading conditions. The measured data were applied to an exemplary standard for wireless communication. The measurement results are highly repeatable and independent of frequency or position/orientation of the EUT and loading conditions.
  • Publication
    Metadata only
    D8.4 Precision Measurement of the Application-dependent Current Consumption of a Wireless Transceiver Chip
    Modern production concepts generate a demand for reliable, fast and secure wireless communication solutions. Therefore, the current consumption should not increase highly due to additional security operations. This paper shows a principle current measurement method exemplarily of a transceiver for IOLink Wireless protocol. The results show that the current consumption increases by about 316 μA when using hardware-based encryption features, whereby an experimental standard deviation of the mean values of about 15 μA was determined.
  • Publication
    Metadata only
    Jetzt kann IO-Link auch funken
    (Beuth Verlag GmbH, 2021-06) ;
    Monaco, Antonio
    ;
  • Publication
    Metadata only
    Design and Development of a Roaming Wireless Safety Emergency Stop
    Modern manufacturing is characterized by a high degree of automation, with autonomous systems also frequently being used. In such environments human intervention in the event of malfunctions or maintenance becomes a rare but also necessary task. When human workers are no longer an integral part of the production process, but only intervene when necessary, e.g., in the case of unexpected machine behavior, appropriate safety solutions will become even more important. This work describes a wireless communication system enabling a flexible and safe emergency stop function for multiple automation cells. A portable emergency stop switch allows seamless transition between different wireless cells, ensuring functional safety. The communication protocol combines IO-Link Wireless features with the safety requirements already implemented in IO-Link Safety. Security requirements are fulfilled through encryption and authentication. The IO-Link Wireless roaming functionality is used to extend the system across several manufacturing cells. An experimental setup confirms the suitability of the system for various applications. The results demonstrate the effectiveness of the handover mechanism and evaluate the potential of the system to improve flexibility, availability and security in dynamic production environments. Future extensions could include the use of AI based evaluation of the radio signals for an intelligent cell handover.
  • Publication
    Metadata only
    Base Station Antenna Placement of Wireless Sensor/Actuator Networks in Manufacturing Cells
    (2019) ;
    Krush, Dmytro
    ;
    Wattar, Housam
    ;
    ;
    Wireless technologies are intensively used in industrial environments and wireless sensor/actuator networks play a key role for highly flexible automation plants, especially within the Industry 4.0 initiative. In order to achieve a highly robust system behavior also an attentive antenna selection and placement within a manufacturing cell is of interest resulting in an enhanced system reserve. In this paper different strategies for base station antenna placement are investigated with the focus on star-topologies, i.e. a central base station and a multitude of remotely located wireless sensors and actuators. A probabilistic approach has been chosen for modeling path loss, multipath fading and coexistence behavior with respect to adjoining manufacturing cells. Also cable attenuation for remote antennas connected to the base station are taken into account.
  • Publication
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    Collision Avoidance and Optimization of Traffic Flow as an Approach for a Smart City Aalen, Germany
    (IEEE, 2024-01) ;
    Kirchheim, Alice
    ;
    Fong, Bernard
    In the last decades, road traffic significantly increased in many regions. As part of sustainable urban areas, the improvement of safety as well as the optimization of traffic flow are important challenges for road mobility. The new mobile communications standard 5G, which is currently being rolled out, is being promoted with a variety of improvements that also address the transport sector. As one component of a smart city approach, a proposed solution to increase road traffic safety and to optimize the traffic flow by means of using 5G is currently being developed and deployed in the city of Aalen, Germany, as part of the "5G-trAAffic" project.
  • Publication
    Open Access
    Developing high-capacity sustainable materials for hydrogen storage
    (UB HSU, 2024)
    Shang, Yuanyuan
    ;
    ;
    Helmut-Schmidt-Universität / Universität der Bundeswehr Hamburg
    ;
    Pundt, Astrid
    ;
    In this thesis, the development of sustainable materials for hydrogen storage is studied. Four model types of hydrogen storage materials are included in this work, which are the complex metal hydride NaAlH₄, solid solution room temperature FeTi alloys, compositionally complex alloys (CCAs), and the reactive hydrides composite (RHC) 2NaBH₄ + MgH₂. The first part of this thesis focuses on developing a complex metal hydride of NaAlH₄ by using waste Al alloy as raw material. The synthesised less pure NaAlH₄ exhibits good reversible hydrogen capacity, whereas the pure NaAlH₄ is not reversible. The second part of this thesis is devoted to developing a FeTi-based metal hydride by using waste steel and Ti alloy scraps as raw materials. Astonishingly, at 50 °C and 100 bar of H₂, the hydrogen storage capacities measured for the FeTi alloys synthesised from recycled scraps are extremely close to the value measured for the pure FeTi. In the third part of this thesis, the hydrogen storage properties of some CCAs are investigated, which further helps in screening the suitable types of waste metal alloys to be used as raw materials. With the synthesised hydrogen storage materials, the main issues are kinetic and thermodynamic tuning. The selected waste steels, Ti alloys, Mg alloys, and Al alloys, are just examples of the vast variety of scrap materials potentially useful for synthesising sustainable hydrogen storage materials. In addition, the influence of single impurities cannot be distinguished. Therefore, the RHC system of 2NaBH₄ + MgH₂ was chosen as a model system to study the effects of well-defined additives on hydrogen storage performances, as can be seen in the last part of this thesis. This work shows that by using waste metal scraps instead of high-purity elements as raw materials, the carbon footprint and costs are tremendously reduced for producing hydrogen storage materials without deteriorating the hydrogen storage properties. This work opens a new path to the development of environmentally sustainable alloys for hydrogen storage purposes.
  • Publication
    Metadata only
    Concept for a Real-Time IoT-Architecture for Collision Avoidance in Smart Cities based on the 5G Mobile Technology
    (IEEE, 2023) ;
    Mousavi, Mohammad Reza
    ;
    Trautwein, Ingo
    ;
    Freymann, Andreas
    ;
    Beutelspacher, Christoph
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    Nehrke, Lara
    ;
    Ludwig, Stephan
    ;
    Kirchheim, Alice
    Road traffic significantly increased in the last decades. The avoidance of accidents and the continuity of traffic flow are significant challenges for road mobility. In this paper, a real-time Internet of Things (IoT) architecture is presented for these current road traffic challenges. The presented architecture takes advantage of the emerging 5G mobile technology and relies on infrastructure components so that the presented architecture can be integrated into city infrastructure to become smarter and provide benefits to citizens. A collision warning service is being implemented to warn road users of imminent collisions. The parallel traffic flow optimization will also enable the prioritization of highlighted traffic partici-pants, such as emergency vehicles. By prioritizing pedestrians, bicycles, e-bikes and buses, for example, it will also be possible to achieve specific traffic and climate policy goals. An according smartphone app allows the resulting advantages to be used in the short term. Furthermore, additional actuators such as displays and signal transmitters will integrate all road users, regardless of the specific app usage. By using 5G, these components will also be implemented quickly, flexibly and reliably as infrastructure IoT devices. The paper concludes with a presentation of a research project in which these solutions are currently being implemented.