@inproceedings{FuhrmannFarmbauerNiemetz, author = {Fuhrmann, Thomas and Farmbauer, Michael and Niemetz, Michael}, title = {Integrating GNU Radio into a Virtual Course about Communication Systems}, series = {44th International Convention on Information, Communication and Electronic Technology (MIPRO): 27.09. - 01.10.2021, Opatija, Croatia}, booktitle = {44th International Convention on Information, Communication and Electronic Technology (MIPRO): 27.09. - 01.10.2021, Opatija, Croatia}, publisher = {IEEE}, isbn = {978-953-233-101-1}, doi = {10.23919/MIPRO52101.2021.9596700}, pages = {1565 -- 1570}, abstract = {Due to the COVID-19 pandemic, the course Communication Systems was transferred from presence to a virtual lecture. No hands-on lab experiments were possible. Therefore, a GNU Radio practical part was integrated into the lecture. A tutorial was written to guide students through the first steps with GNU Radio to decrease initial problems and increase student motivation. Several examples were given regarding digital signal processing, analogue and digital modulation and demodulation. Software Defined Radio receivers were set up in the amateur radio lab of the university and connected to the internet so that students were able to get real radio data to be analyzed and demodulated with their own GNU Radio models. This enables a knowledge transfer from simulated signal processing to the analysis and demodulation of real live signals. Students showed medium to high interest in practical examples during the lectures and tried their own GNU Radio simulations. Overall, the integration of GNU Radio and Software Defined Radio receivers into this virtual lecture gave additional benefits for the students to deal with signal processing and demodulation experiments. It is planned to use GNU Radio in the future for complementary practical examples to the hands-on experiments in the lab.}, language = {en} } @inproceedings{DeubzerHobelsbergerMottoketal., author = {Deubzer, Michael and Hobelsberger, Martin and Mottok, J{\"u}rgen and Schiller, Frank and Dumke, Reiner and Siegle, Markus and Margull, Ulrich and Niemetz, Michael and Wirrer, Gerhard}, title = {Modeling and Simulation of Embedded Real-Time Multi-Core Systems}, series = {Proceedings of the 3rd Embedded Software Engineering Congress, 7. bis 9. Dezember 2010, Sindelfingen}, booktitle = {Proceedings of the 3rd Embedded Software Engineering Congress, 7. bis 9. Dezember 2010, Sindelfingen}, language = {en} } @inproceedings{HobelsbergerDumkeMottoketal., author = {Hobelsberger, Martin and Dumke, Reiner and Mottok, J{\"u}rgen and Niemetz, Michael and Wirrer, Gerhard}, title = {An Experience-Based Repository of Reusable Components for an Component-Based Automotive Software System}, series = {Applied Software Measurement, proceedings of the joined International Conferences on Software Measurement IWSM/MetriKon/Mensura 2010, 10.-12. November 2010, Stuttgart, Germany}, booktitle = {Applied Software Measurement, proceedings of the joined International Conferences on Software Measurement IWSM/MetriKon/Mensura 2010, 10.-12. November 2010, Stuttgart, Germany}, pages = {218 -- 240}, language = {en} } @inproceedings{DeubzerMargullMottoketal., author = {Deubzer, Michael and Margull, Ulrich and Mottok, J{\"u}rgen and Niemetz, Michael and Wirrer, Gerhard}, title = {Partitionierungs-Scheduling von Automotive Restricted Tasksystemen auf Multiprozessorplattformen}, series = {Proceedings of the 2nd Embedded Software Engineering Congress, 8. bis 10. Dezember 2009, Sindelfingen}, booktitle = {Proceedings of the 2nd Embedded Software Engineering Congress, 8. bis 10. Dezember 2009, Sindelfingen}, pages = {536 -- 542}, language = {de} } @inproceedings{DeubzerMargullMottoketal., author = {Deubzer, Michael and Margull, Ulrich and Mottok, J{\"u}rgen and Niemetz, Michael and Wirrer, Gerhard}, title = {Partly Proportionate Fair Multiprocessor Scheduling of Heterogeneous Task Systems}, series = {5th Embedded Real Time Software and Systems Conference, May 2010}, booktitle = {5th Embedded Real Time Software and Systems Conference, May 2010}, abstract = {Proportionate fair (Pfair) scheduling, which allows task migration at runtime and assigns each task processing time with regard to its weight, is one of the most efficient group of SMP multiprocessor scheduling algorithms known up to now. Drawbacks are tight requirements to the task system, namely the restriction to periodic task systems with synchronized task activation, quantized task execution time, and implicit task deadline. Most likely, a typical embedded real-time system does not fulfill these requirements. In this paper we address violations of these requirements. For heterogeneous task systems, we define the multiple time base (MTB) task system, which is a less pessimistic model than sporadic task systems and is used for automotive systems. We apply the concept of Pfair scheduling to MTB task systems, called partly proportionate fair (Partly-Pfair) scheduling. The restrictions on MTB task systems required for Partly-Pfair ness are weaker than restrictions on periodic task systems required for Pfair ness. In a simulation based study we examined the performance of Partly-Pfair-PD and found it capable to schedule feasible MTB task sets causing a load of up to 100\% of the system capacity.}, language = {en} } @inproceedings{AltmannBirknerHaeckletal., author = {Altmann, Andreas and Birkner, Wolfgang and H{\"a}ckl, Franz-Xaver and Hanner, Christopher and Liebhart, Peter and Metschl, Samuel and Weck, Florian and Farmbauer, Michael and Heiß, Manfred and Cuno, H.-H. and Fuhrmann, Thomas and Mandl, Roland and Mottok, J{\"u}rgen and Niemetz, Michael}, title = {Payload development and launch of a stratosphere balloon mission}, series = {IEEE Global Engineering Education Conference (EDUCON 2014), 3-5 April 2014, Istanbul, Turkey}, booktitle = {IEEE Global Engineering Education Conference (EDUCON 2014), 3-5 April 2014, Istanbul, Turkey}, doi = {10.1109/EDUCON.2014.6826065}, abstract = {During a student project a stratosphere balloon was developed and launched. This project included the definition of the balloon parameters and the scientific instruments for performing atmospheric measurements, the development of all mechanical and electronic parts, the administration of the project as well as the management tasks related to the balloon launch. The main challenge for the students was the high complexity of the project due to tasks involving many different knowledge domains and the long project duration from the initial definition to the launch.}, language = {en} } @inproceedings{SchmidhuberDeubzerMaderetal., author = {Schmidhuber, Stefan and Deubzer, Michael and Mader, Ralph and Niemetz, Michael and Mottok, J{\"u}rgen}, title = {Towards the Derivation of Guidelines for the Deployment of Real-Time Tasks on a Multicore Processor}, series = {4th International Symposium on Model-Based Safety and Assessment (IMBSA 2014), Munich, Germany, October 27-29, 2014, Proceedings}, booktitle = {4th International Symposium on Model-Based Safety and Assessment (IMBSA 2014), Munich, Germany, October 27-29, 2014, Proceedings}, publisher = {Springer}, address = {Munich}, isbn = {978-3-319-12213-7}, doi = {10.1007/978-3-319-12214-4_12}, pages = {152 -- 165}, abstract = {The deployment of automotive software on a multicore processor includes the task of mapping executables to cores. Given the number of possible solutions, integrators have to solve a complex problem. Considering multiple, often conflicting goals like minimizing task response times and memory consumption, complexity further increased with the advent of multicore processors. We present a model-based approach for deriving design rules supporting integrators with statically mapping tasks to a multicore ECU. First, an evolutionary algorithm is used to sample the design space. For each sample, a model-based analysis is performed, resulting in the required fitness values according to the system metric objectives. Finally, subsets of the sample population are used to derive deployment guidelines by evaluating similarities between highly ranked solutions. This reduces the number of solutions to be considered by the integrators by orders of magnitude. In a case-study, we demonstrate the developed approach on an artificial automotive engine management system.}, language = {en} } @inproceedings{AlfransederKrapfMaderetal., author = {Alfranseder, Martin and Krapf, Tobias and Mader, Ralph and Niemetz, Michael and Mottok, J{\"u}rgen and Siemers, Christian}, title = {An Efficient Partitioning Strategy for Runnables in Weakly Dependent Tasks on Embedded Multi-Core Systems}, series = {Embedded real-time software and systems (ERTS² 2014), Feb 2014, Toulouse, France}, booktitle = {Embedded real-time software and systems (ERTS² 2014), Feb 2014, Toulouse, France}, abstract = {With multi-core controllers entering the area of automotive control ECUs, strategies for parallelizing the control- algorithms come into focus. This paper deals with a special part of automotive powertrain software, called state transitions. Since dependencies between runnables executed there are weak, the transitions provide a good basis for parallelization. We present a strategy of how to distribute efficiently the execution of runnables to different cores while taking care of inner and outer dependencies. The strategy is accompanied by two case studies demonstrating the performance of the concept. The first one is carried out to find the most efficient strategies of parallelize state transitions based on randomly generated, simulated state transitions. In the second one, the developed partitioning strategies are applied to a real software project for an automotive powertrain system.}, language = {en} } @inproceedings{AlfransederMuchaSchmidhuberetal., author = {Alfranseder, Martin and Mucha, Matthias and Schmidhuber, Stefan and Sailer, Andreas and Niemetz, Michael and Mottok, J{\"u}rgen}, title = {A modified synchronization model for dead-lock free concurrent execution of strongly interacting task sets in embedded systems}, series = {2013 International Conference on Applied Electronics (AE 2013), IEEE, 10-12 September 2013, Pilsen, Czech Republic}, volume = {18}, booktitle = {2013 International Conference on Applied Electronics (AE 2013), IEEE, 10-12 September 2013, Pilsen, Czech Republic}, pages = {13 -- 18}, abstract = {Global scheduling algorithms are very promising for application in embedded real-time systems using multi-core controllers. In this paper we want to make a first step forward to apply such scheduling methods on real existing systems. Especially a new resource model is necessary to avoid deadlocks, as this goal can not be achieved by using the standard OSEK Priority Ceiling Protocol when shared global resources are in use. We also introduce the new metric mean Normalized Blocking Time in order to be able to compare locking mechanisms according to the timing effects of their blocking behavior. Finally we give a simulative application example of the new metric by the use of two different kinds of semaphore models and an example task set typical for existing embedded real-time systems in the automotive powertrain environment.}, language = {en} } @inproceedings{SchummJosephMottoketal., author = {Schumm, Michael and Joseph, Saskia and Mottok, J{\"u}rgen and Niemetz, Michael and Schroll-Decker, Irmgard}, title = {Lernarrangements im software engineering und deren evaluation - neue konzepte f{\"u}r hochschule und lebenslanges Lernen}, series = {Tagungsband 5th Embedded Software Engineering Kongress, 3. bis 7. Dezember 2012, Sindelfingen}, booktitle = {Tagungsband 5th Embedded Software Engineering Kongress, 3. bis 7. Dezember 2012, Sindelfingen}, language = {de} } @inproceedings{JupkeReindlMeieretal., author = {Jupke, Michael and Reindl, Andrea and Meier, Hans and Niemetz, Michael}, title = {Bidirectional DC-DC Converter with Digital Droop Parameterization}, series = {26th 2021 International Conference on Applied Electronics (AE): 7-8 Sept. 2021 Pilsen, Czech Republic}, booktitle = {26th 2021 International Conference on Applied Electronics (AE): 7-8 Sept. 2021 Pilsen, Czech Republic}, editor = {Pinker, Jiř{\´i}}, publisher = {Institute of Electrical and Electronics Engineers}, isbn = {978-80-261-0972-3}, doi = {10.23919/AE51540.2021.9542920}, pages = {1 -- 6}, abstract = {The key for decentralized battery systems is a robust and communication-less control strategy for autonomous power sharing of parallel-connected DC-DC converters. Battery systems improve the reliability and quality of power supply in renewable energy systems and enable power supply for off-grid, mobile applications, including islanded grids, home storage, and electric vehicles. In many cases, components with different electrical properties require different voltage levels. An adaptation is consequently essential and is normally implemented in DC grids for the batteries via bidirectional DC-DC converters. The power flow in both directions can thus be ensured. To achieve a power distribution in parallel connected DC-DC converters, a droop control in the form of a virtual internal resistor can be used. This paper presents a novel approach of a DC-DC converter with a digitally parameterizable droop resistor, whose voltage regulation is based on an analog operational amplifier circuit to ensure low delays and robustness. The droop resistor is adjusted with a microcontroller, which offers the possibility to apply a higher-level control for load sharing via an interface. Mathematical correlations are used to clearly define the parameters of the control. Furthermore, the circuit was completely simulated and tested in the hardware setup. The shown results verify the functionality and indicate only minor deviations. Therefore, this circuit is important for future use in distributed battery systems.}, language = {en} } @inproceedings{ReindlMeierNiemetz, author = {Reindl, Andrea and Meier, Hans and Niemetz, Michael}, title = {Scalable, Decentralized Battery Management System Based on Self-organizing Nodes}, series = {Architecture of computing systems - ARCS 2020: 33rd international conference, Aachen, Germany, May 25-28, 2020, proceedings}, volume = {12155}, booktitle = {Architecture of computing systems - ARCS 2020: 33rd international conference, Aachen, Germany, May 25-28, 2020, proceedings}, editor = {Brinkmann, Andr{\´e} and Karl, Wolfgang and Lankes, Stefan and Tomforde, Sven and Pionteck, Thilo and Trinitis, Carsten}, publisher = {Springer International Publishing}, address = {Cham}, isbn = {978-3-030-52793-8}, doi = {10.1007/978-3-030-52794-5_13}, pages = {171 -- 184}, abstract = {Due to the transition to renewable energy sources and the increasing share of electric vehicles and smart grids, batteries are gaining in importance. Battery management systems (BMSs) are required for optimal, reliable operation. In this paper, existing BMS topologies are presented and evaluated in terms of reliability, scalability and flexibility. The decentralisation of BMSs and associated advantages are shown. A scalable, reconfigurable BMS based on a distributed architecture of self-organized, locally controlled nodes is proposed. For distributed system control, producers, batteries and consumers each are equipped with a local microcontroller based control unit, which monitors and controls the local parameters with its own computing and communication resources. Features, advantages and challenges to overcome of the proposed approach are described.}, language = {en} } @inproceedings{HerboldReindlMeieretal., author = {Herbold, Florian and Reindl, Andrea and Meier, Hans and Niemetz, Michael and Kr{\"a}mer, Stefan}, title = {Secure Software Updates: Challenges and Solutions for Embedded IoT Systems}, series = {Proceedings of the 9th Embedded Systems Workshop: July 1-3, 2021 Horomerice, Czech Republic}, booktitle = {Proceedings of the 9th Embedded Systems Workshop: July 1-3, 2021 Horomerice, Czech Republic}, editor = {Kub{\´a}tov{\´a}, Hana and Fišer, Petr and Boreck{\´y}, Jaroslav}, isbn = {978-80-01-06858-8}, pages = {5 -- 13}, abstract = {The invention of the internet made the development of intelligent networking of millions of embedded systems possible. This enabled smart buildings, power grids and cities as well as applications in the fields of health, agriculture and industry. These systems frequently perform safety-critical applications and operations. This makes it urgent to protect these sensible systems as effectively as possible. Especially firmware updates are often the weak point in the systems. If unauthorised persons gain access to the system during the update, malware can be injected or sensitive data can be read and stolen. This paper describes the challenges of secure firmware updates. To protect an embedded system from potential attackers, the concepts integrity, authenticity and confidentiality have to be adhered during the update process. Otherwise, there is an increased risk of modifying or reverse engineering the firmware image. Likewise, inadequately protected software can enable the installation of third-party firmware as well as the installation of firmware on a third-party system. Threat prevention is presented with solutions derived from functional safety and IT security. Aspects of protection against errors in the transmission of updates and against attacks aiming to compromise the system are explained. Finally, a possible sequence of a secure update process is examined in detail for a real embedded system implementation. For this purpose, the preparation, transmission and installation of a firmware update in the bootloader are discussed}, language = {en} } @inproceedings{SchummJosephSchrollDeckeretal., author = {Schumm, Michael and Joseph, Saskia and Schroll-Decker, Irmgard and Niemetz, Michael and Mottok, J{\"u}rgen}, title = {Required competences in software engineering - pair programming as an instrument for facilitating life-long learning}, series = {15th International Conference on Interactive Collaborative Learning and 41st International Conference on Engineering Pedagogy, Villach}, booktitle = {15th International Conference on Interactive Collaborative Learning and 41st International Conference on Engineering Pedagogy, Villach}, doi = {10.1109/ICL.2012.6402229}, abstract = {The professional requirements in software engineering have become highly volatile due to the complexities of project development and rapid and innovative changes occurring in the field. Therefore, the development of inter-personal and social competences has gained central importance in the training of software developers. The following text will present a concept allowing to acquire competences by using Pair Programming as an instrument. Moreover, arrangements for learning and teaching will be presented facilitating the acquisition of these competences. By approaching the issue of competence acquisition on a technical as well as on an educational and social level, lifelong learning is facilitated and supported.}, language = {en} } @inproceedings{AbkeBruneHauptetal., author = {Abke, J{\"o}rg and Brune, Philipp and Haupt, Wolfram and Hagel, Georg and Landes, Dieter and Mottok, J{\"u}rgen and Niemetz, Michael and Pfeiffer, Volkhard and Studt, Reimer and Schroll-Decker, Irmgard and Sedelmaier, Yvonne}, title = {Evelin - ein Forschungsprojekt zur systematischen Verbesserung des Lernens von Software Engineering}, series = {Tagungsband 5th Embedded Software Engineering Kongress, 3. bis 7. Dezember 2012, Sindelfingen}, booktitle = {Tagungsband 5th Embedded Software Engineering Kongress, 3. bis 7. Dezember 2012, Sindelfingen}, isbn = {978-3-8343-2407-8}, pages = {653 -- 658}, language = {de} } @inproceedings{JosephSchummSchrollDeckeretal., author = {Joseph, Saskia and Schumm, Michael and Schroll-Decker, Irmgard and Niemetz, Michael and Mottok, J{\"u}rgen}, title = {Anmerkungen zur Kompetenz-Performanz-Relation: Software Engineering im Spannungsfeld der beruflichen Anforderungen}, series = {Tagungsband 5th Embedded Software Engineering Kongress, 3. bis 7. Dezember 2012, Sindelfingen}, booktitle = {Tagungsband 5th Embedded Software Engineering Kongress, 3. bis 7. Dezember 2012, Sindelfingen}, language = {de} } @inproceedings{ReindlMeierNiemetzetal., author = {Reindl, Andrea and Meier, Hans and Niemetz, Michael and Park, Sangyoung}, title = {Decentralized Battery Management System with Customized Hardware Components}, series = {IEEE 19th Student Conference on Research and Development (SCOReD), Sustainable Engineering and Technology towards Industry Revolution: 23-25 Nov. 2021, Kota Kinabalu, Malaysia}, booktitle = {IEEE 19th Student Conference on Research and Development (SCOReD), Sustainable Engineering and Technology towards Industry Revolution: 23-25 Nov. 2021, Kota Kinabalu, Malaysia}, publisher = {IEEE}, doi = {10.1109/SCOReD53546.2021.9652737}, pages = {350 -- 355}, abstract = {With an increasing number of sold electric vehicles (EVs), a large number of used batteries will be at disposal. How to deal with these resources is one of the major challenges in reducing the environmental impact of batteries throughout their entire life cycle. Heterogeneous cell parameters due to the different usage histories are a challenge for second-life use. The effort and cost of remanufacturing required to test and assemble a new battery pack is a further concern. Systems that combine battery packs/modules without full reassembly offer advantages such as cost and reusability. A decentralized battery management system (DBMS) provides a suitable architecture for such systems involving different types of batteries. In this paper, an architecture for a decentralized, battery state-dependent control is shown. The proposed DBMS supports various types of batteries, is scalable and flexibly adaptable for a wide range of applications. Despite the significant advantages, there are increased requirements to meet for the hardware implementation and the applied control strategies. Therefore, the necessary hardware components and their requirements are described and the hardware implementations are provided.}, language = {en} } @inproceedings{NiemetzFuhrmannFarmbauer, author = {Niemetz, Michael and Fuhrmann, Thomas and Farmbauer, Michael}, title = {Comprehensive Amateur Radio Education including Public Outreach}, series = {IEEE Integrated STEM Education Conference (ISEC), 16-16 March 2019, Princeton, NJ, USA}, booktitle = {IEEE Integrated STEM Education Conference (ISEC), 16-16 March 2019, Princeton, NJ, USA}, publisher = {IEEE}, doi = {10.1109/ISECon.2019.8882078}, pages = {98 -- 103}, abstract = {An amateur radio lecture was developed and is conducted within the general education program of the Ostbayerische Technische Hochschule Regensburg. This course enables the students to participate in a variety of activities within the university. Different learning formats for communication engineering are carried out in combination with an amateur radio station of the university. Additionally, some of the projects serve as anchor points for increased visibility of the university in local society, e.g. by carrying out public events in connection with the local amateur radio community. It is seen that this course together with the amateur radio station have several positive effects for technical education and university visibility.}, language = {en} } @inproceedings{ReindlSingerMeieretal., author = {Reindl, Andrea and Singer, Thomas and Meier, Hans and Niemetz, Michael and Park, Sangyoung}, title = {Framework to Test DC-DC Converters Developed for a Decentralized Battery Management System}, series = {2021 International Conference on Applied Electronics (AE): 7-8 Sept. 2021, Pilsen, Czech Republic}, booktitle = {2021 International Conference on Applied Electronics (AE): 7-8 Sept. 2021, Pilsen, Czech Republic}, publisher = {IEEE}, doi = {10.23919/AE51540.2021.9542882}, pages = {1 -- 6}, abstract = {DC- DC converters control the power flow and thus the power distribution between the components on different voltage levels. They are essential for (dis)charging batteries and influence the safety and stability of the entire battery management system (BMS). Therefore, testing the functionality and the reliability of DC-DC converters is crucial. This is especially true for decentralized battery management systems (DBMS), where multiple nodes communicate to collectively control the system. The used DC-DC converters are modified to parameterize them during operation via microcontroller interfaces. Integrating the communication into the control loop requires an analysis of the control behavior due to additional delays. Therefore, this paper proposes a framework to test DC-DC converters considering the control and communication perspectives. The response time, the control accuracy and stability of these DC-DC converters, e.g., under continuous and abrupt load changes, are measured in automated tests. The dedicated software framework simulates the DBMS and stimulates the hardware components (e.g. electronic loads, data acquisition) via respective interfaces (CAN, RS232). This allows the test of various DC-DC converters with flexibly adaptable load and power generation profiles. An initial application validates the test framework by verifying the aforementioned aspects and thus the applicability of a DC-DC converter within the DBMS.}, language = {en} } @inproceedings{FuhrmannNiemetz, author = {Fuhrmann, Thomas and Niemetz, Michael}, title = {Planned Chaos in Electrical Engineering Education}, series = {6th International Conference on Higher Education Advances (HEAd'20): 02.06.2020 - 05.06.2020, Valencia}, booktitle = {6th International Conference on Higher Education Advances (HEAd'20): 02.06.2020 - 05.06.2020, Valencia}, publisher = {Universitat Polit{\`e}cnica de Val{\`e}ncia}, isbn = {9788490488119}, doi = {10.4995/head20.2020.10989}, abstract = {This paper presents the idea to intentionally introduce planned chaos into electrical engineering lectures and lab courses to improve students' learning success. The reason to present this idea are several personal experiences in daily teaching. If students experience some uncertainty in their study program, it is seen that they have higher challenges and therefore higher learning success in managing uncertain situations. In these ways, students acquire methodical and social competences to deal with uncertainty and achieve productive results in an unstable working environment. If, however, the chaos is too large, students are over-strained with the situation, distracted from the actual learning targets and consequently learning results will be worse, drop-out rates will increase and they will be frustrated. The beneficial level of uncertainty depends on the student culture, academic progress and personality characteristics. The competence to deal with complex situations is essential for later professional life where unexpected circumstances occur regularly. Introducing planned chaos into lectures and lab courses has not to be confused with a missing didactic concept and is no justification for a bad preparation. Planned chaos is a demanding concept for professors to find the right implementation for an optimized learning outcome. These described findings are experienced from practical work and student evaluations.}, language = {en} }