@article{KraemerMottokMeier, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans}, title = {Multi-Core Scheduling in Embedded Systemen, Teil 3}, series = {Hanser Automotive}, journal = {Hanser Automotive}, number = {5-6}, pages = {14 -- 16}, language = {en} } @inproceedings{RaabKraemerMottoketal., author = {Raab, Peter and Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans and Racek, Stanislav}, title = {Safe software processing by concurrent execution in a real-time operating system}, series = {16th International Conference on Applied Electronics (AE 2011), 2011, Pilsen, Czech Republic}, booktitle = {16th International Conference on Applied Electronics (AE 2011), 2011, Pilsen, Czech Republic}, pages = {315 -- 319}, abstract = {The requirements for safety-related software systems increases rapidly. To detect arbitrary hardware faults, there are applicable coding mechanism, that add redundancy to the software. In this way it is possible to replace conventional multi-channel hardware and so reduce costs. Arithmetic codes are one possibility of coded processing and are used in this approach. A further approach to increase fault tolerance is the multiple execution of certain critical parts of software. This kind of time redundancy is easily realized by the parallel processing in an operating system. Faults in the program flow can be monitored. No special compilers, that insert additional generated code into the existing program, are required. The usage of multi-core processors would further increase the performance of such multi-channel software systems. In this paper we present the approach of program flow monitoring combined with coded processing, which is encapsulated in a library of coded data types. The program flow monitoring is indirectly realized by means of an operating system.}, 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{BlankBrunnerFuhrmannetal., author = {Blank, M. and Brunner, Stefan and Fuhrmann, Thomas and Meier, Hans and Niemetz, Michael}, title = {Embedded Linux in engineering education}, series = {2015 IEEE Global Engineering Education Conference (EDUCON), 18-20 March 2015, Tallinn, Estonia}, booktitle = {2015 IEEE Global Engineering Education Conference (EDUCON), 18-20 March 2015, Tallinn, Estonia}, publisher = {IEEE}, doi = {10.1109/EDUCON.2015.7095964}, pages = {145 -- 150}, abstract = {With the availability of cost effective embedded Linux solutions and the increasing complexity of embedded devices because of growing calculation power and communication demand, Linux is getting increasingly interesting as an operating system for the design of embedded control solutions. This is the case for almost all technical applications in electrical engineering like energy distribution systems, high level communication, signal processing or industrial automation. In the engineering master courses at the OTH Regensburg, a lecture is offered introducing students to Linux with a strong focus on embedded applications. This paper describes the concept of the lecture including the laboratory set up and gives some examples of embedded Linux projects performed by students.}, language = {en} } @article{ReindlZhengSchwarzetal., author = {Reindl, Klaus and Zheng, Yuanhang and Schwarz, Andreas and Meier, Stefan and Maas, Roland and Sehr, Armin and Kellermann, Walter}, title = {A stereophonic acoustic signal extraction scheme for noisy and reverberant environments}, series = {Computer Speech and Language}, volume = {27}, journal = {Computer Speech and Language}, number = {3}, publisher = {Elsevier}, doi = {10.1016/j.csl.2012.07.011}, pages = {726 -- 745}, abstract = {In this contribution, a novel two-channel acoustic front-end for robust automatic speech recognition in adverse acoustic environments with nonstationary interference and reverberation is proposed. From a MISO system perspective, a statistically optimum source signal extraction scheme based on the multichannel Wiener filter (MWF) is discussed for application in noisy and underdetermined scenarios. For free-field and diffuse noise conditions, this optimum scheme reduces to a Delay \& Sum beamformer followed by a single-channel Wiener postfilter. Scenarios with multiple simultaneously interfering sources and background noise are usually modeled by a diffuse noise field. However, in reality, the free-field assumption is very weak because of the reverberant nature of acoustic environments. Therefore, we propose to estimate this simplified MWF solution in each frequency bin separately to cope with reverberation. We show that this approach can very efficiently be realized by the combination of a blocking matrix based on semi-blind source separation ('directional BSS'), which provides a continuously updated reference of all undesired noise and interference components separated from the desired source and its reflections, and a single-channel Wiener postfilter. Moreover, it is shown, how the obtained reference signal of all undesired components can efficiently be used to realize the Wiener postfilter, and at the same time, generalizes well-known postfilter realizations. The proposed front-end and its integration into an automatic speech recognition (ASR) system are analyzed and evaluated in noisy living-room-like environments according to the PASCAL CHiME challenge. A comparison to a simplified front-end based on a free-field assumption shows that the introduced system substantially improves the speech quality and the recognition performance under the considered adverse conditions.}, language = {de} } @inproceedings{LegrandBoeseErmertetal., author = {Legrand, Virginie and B{\"o}se, Holger and Ermert, Helmut and Freimuth, Herbert and Baumann, Michael and Egersd{\"o}rfer, Stefan and Meier, Alexander and Dragoi, Daniel}, title = {Technologien f{\"u}r haptische Systeme in der Informations{\"u}bertragung}, series = {IAFW Tagung - Lengenfeld, Mai 2003}, booktitle = {IAFW Tagung - Lengenfeld, Mai 2003}, language = {de} }