@inproceedings{RaabRacekKraemeretal., author = {Raab, Peter and Racek, Stanislav and Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen}, title = {Data Flow Analysis of Software Executed by Unreliable Hardware}, series = {16th Euromicro Conference on Digital System Design, Los Alamitos, CA, USA}, booktitle = {16th Euromicro Conference on Digital System Design, Los Alamitos, CA, USA}, doi = {10.1109/DSD.2013.35}, pages = {243 -- 249}, abstract = {The data flow is a crucial part of software execution in recent applications. It depends on the concrete implementation of the realized algorithm and it influences the correctness of a result in case of hardware faults during the calculation. In logical circuits, like arithmetic operations in a processor system, arbitrary faults become a more tremendous aspect in future. With modern manufacturing processes, the probability of such faults will increase and the result of a software's data flow will be more vulnerable. This paper shows a principle evaluation method for the reliability of a software's data flow with arbitrary soft errors also with the concept of fault compensation. This evaluation is discussed by means of a simple example based on an addition.}, language = {en} } @inproceedings{KraemerRaabMottoketal., author = {Kr{\"a}mer, Stefan and Raab, Peter and Mottok, J{\"u}rgen and Racek, Stanislav}, title = {Reliability analysis of real-time scheduling by means of stochastic simulation}, series = {2012 International Conference on Applied Electronics (AE 2012), Pilsen, Czech Republic, 5 - 7 September 2012}, booktitle = {2012 International Conference on Applied Electronics (AE 2012), Pilsen, Czech Republic, 5 - 7 September 2012}, pages = {151 -- 156}, abstract = {We present a simulation-based approach to reliability analysis combined with a schedulability analysis of software intensive embedded real-time systems. In such a system not only does the software execution have to be hardened against soft errors, e.g., by means of coded processing or diverse execution, but also the real-time requirements have still to be met in the presence of such error to guarantee a safe operation of the system. For that reason, the influence regarding the real-time characteristics of a given sporadic error with a certain error rate is analyzed by means of a Monte Carlo simulation. Different safety design patterns are introduced and compared. Furthermore, the impact on the schedulability of an embedded system is discussed.}, language = {en} } @inproceedings{RaabRacekKraemeretal., author = {Raab, Peter and Racek, Stanislav and Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen}, title = {Reliability of Task Execution during Safe Software Processing}, series = {15th Euromicro Conference on Digital System Design, Cesme, Turkey}, booktitle = {15th Euromicro Conference on Digital System Design, Cesme, Turkey}, doi = {10.1109/DSD.2012.110}, pages = {84 -- 89}, abstract = {This paper presents the reliability evaluation of task execution during safe software processing. The standard method of duplication in a safety-critical application can also be applied for tasks in a software system. But in addition to this, there is also the possibility for coded task processing to increase the reliability and availability of software. The presented analysis covers the reliability analysis of a single, a duplicated and a coded task by the technique of continuous time Markov processes. Markov processes are often used for the reliability evaluation of safety-critical systems. We introduce a method to describe the execution time of tasks by means of enhanced Markov models and their solution by numerical methods.}, language = {en} } @inproceedings{KraemerRaabMottok, author = {Kr{\"a}mer, Stefan and Raab, Peter and Mottok, J{\"u}rgen}, title = {Simulationsbasierte Reliability-Analyse - Einfl{\"u}sse von zuf{\"a}lligen Fehlern auf das Echtzeit-Scheduling}, 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}, pages = {613 -- 622}, language = {de} } @article{RaabKraemerMottok, author = {Raab, Peter and Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen}, title = {Reliability of data processing and fault compensation in unreliable arithmetic processors, Microprocessors and Microsystems}, series = {Microprocessors and Microsystems}, volume = {40}, journal = {Microprocessors and Microsystems}, number = {Februar}, publisher = {Elsevier}, doi = {10.1016/j.micpro.2015.07.014}, pages = {102 -- 112}, abstract = {In logical circuits, like arithmetic operations in a processor system, arbitrary faults become a more tremendous aspect in future. Modern manufacturing processes lead to less reliability and higher vulnerability of software execution to soft-errors. The correctness of certain results is important especially for safety-critical applications whose reliability depends on the fault-free execution of each single instruction and the dependencies between them. The more complex a software is the more unreliable the outcome is. But, there is a contrary effect. If the probability for multiple faults increases, there is also the chance that two faults compensate each other and the result is correct again. This paper presents the basic ideas for such a reliability evaluation of a software's data flow with arbitrary soft-errors and the effect of fault compensation. Further, this evaluation provides a possibility to compare different implementations of a data flow with respect to the reliability. This is shown by the comparison of two different error codes as alternatives for coded data processing.}, language = {en} } @inproceedings{KraemerMottokRacek, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Racek, Stanislav}, title = {Proportionate fair based multicore scheduling for fault tolerant multicore real-time systems}, series = {International Conference on Electrical and Information Technologies (ICEIT), 25-27 March 2015, Marakesch, Morocco}, booktitle = {International Conference on Electrical and Information Technologies (ICEIT), 25-27 March 2015, Marakesch, Morocco}, doi = {10.1109/EITech.2015.7162952}, pages = {88 -- 93}, abstract = {In this paper we present a scheduling approach for safety critical, fault tolerant, multicore real-time embedded systems. For this kind of systems, not only the correctness of a computed result but also the strict adherence to timing requirements of computation is essential to avoid any kind of damage. To react to unpredictable, arbitrary hardware faults suitable error detection mechanisms have to be applied. The caused error itself and the detection and correction have great impact on the system's timing behavior. To still keep the real-time requirements, the used scheduling algorithm has to ensure maximum flexibility to disturbances of the timing. The group of Proportionate Fair (Pfairness) multicore scheduling algorithms has been proven to create an optimal schedule in polynomial time. The contribution of this paper is a Pfair-based algorithm that uses tight coupling between the error detection mechanisms and the scheduler of the real-time operating system to establish a loop-back connection.}, language = {en} } @inproceedings{KraemerMottokMeier, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans}, title = {Modifikation des Taskzustandsmodells des LLREF-Schedulers auf einem Dual-Core-Prozessor}, 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 = {628 -- 636}, language = {de} } @inproceedings{KraemerMottokMeier, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans}, title = {Osek-basierende Implementierung des LLREF-Scheduling-Algorithmus f{\"u}r eine Dual-Core-Architektur}, series = {2. Landshuter Symposium Mikrosystemtechnik, Tagungsband, 24. une 25. Februar 2010, Hochschule Landshut}, booktitle = {2. Landshuter Symposium Mikrosystemtechnik, Tagungsband, 24. une 25. Februar 2010, Hochschule Landshut}, pages = {343 -- 349}, language = {de} } @inproceedings{RaabKraemerMottok, author = {Raab, Peter and Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen}, title = {Cyclic codes and error detection during data processing in embedded software systems}, series = {Proceedings of the 4rd Embedded Software Engineering Congress (ESE), 5.-9. Dezember 2011, Sindelfingen}, booktitle = {Proceedings of the 4rd Embedded Software Engineering Congress (ESE), 5.-9. Dezember 2011, Sindelfingen}, pages = {577 -- 590}, language = {en} } @article{KraemerMottokMeier, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans}, title = {Multi-Core Scheduling in Embedded Systemen, Teil 1}, series = {Hanser Automotive}, journal = {Hanser Automotive}, number = {1-2}, pages = {18 -- 22}, language = {en} } @article{KraemerMottokMeier, author = {Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Meier, Hans}, title = {Multi-Core Scheduling in Embedded Systemen, Teil 2}, series = {Hanser Automotive}, journal = {Hanser Automotive}, number = {3-4}, pages = {23 -- 25}, language = {en} } @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} } @article{RaabKraemerMottoketal., author = {Raab, Peter and Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen and Vavricka, Vlastimil}, title = {Isomorphism between Linear Codes and Arithmetic Codes for Safe Data Processing in Embedded Software Systems}, series = {Computing and Informatics (CAI)}, volume = {33}, journal = {Computing and Informatics (CAI)}, pages = {721 -- 734}, abstract = {We present a transformation rule to convert linear codes into arithmetic codes. Linear codes are usually used for error detection and correction in broadcast and storage systems. In contrast, arithmetic codes are very suitable for protection of software processing in computer systems. This paper shows how to transform linear codes protecting the data stored in a computer system into arithmetic codes safeguarding the operations built on this data. Combination of the advantages of both coding mechanisms will increase the error detection capability in safety critical applications for embedded systems by detection and correction of arbitrary hardware faults.}, language = {en} } @inproceedings{KraemerRaabMottoketal., author = {Kr{\"a}mer, Stefan and Raab, Peter and Mottok, J{\"u}rgen and Racek, Stanislav}, title = {Comparison of Enhanced Markov Models and Discrete Event Simulation - for evaluation of probabilistic Faults in safety-critical real-time task sets}, series = {Proceedings of EUROMICRO DSD 2014 - 17th Euromicro Conference on Digital System Design}, booktitle = {Proceedings of EUROMICRO DSD 2014 - 17th Euromicro Conference on Digital System Design}, doi = {10.1109/DSD.2014.42}, pages = {591 -- 598}, abstract = {In this paper we present simulation and model based approaches for evaluating and validating the temporal and safety relevant properties of software intensive safety-critical real-time embedded systems. A high level reliability model of a safe task execution is described by a continuous-time Markov process, enhanced by the modeling of execution times. It is shown that the behavior - regarding real-time and safety metrics - of this theoretical model can be transferred into an abstract system timing model, which then can be analyzed by a discrete event simulation approach. The verification of the discrete event simulation by Markov models offers the possibility of a holistic approach for reliability analysis combined with schedulability analysis of complex safety-critical multicore real-time systems by the discrete event simulation.}, language = {en} } @inproceedings{KraemerSimsekBraunetal., author = {Kr{\"a}mer, Stefan and Simsek, Erol and Braun, J{\"u}rgen and Deubzer, Michael and Stingl, Armin and Hobelsberger, Martin and Mottok, J{\"u}rgen}, title = {Mut zu Fehlern, um die Qualit{\"a}t zu steigern - Fault-Injection zur Steigerung der Zuverl{\"a}ssigkeit}, series = {Tagungsband, 6th Embedded Software Engineering, Kongress 2013, 2. bis 6. Dezember 2013, Sindelfingen}, booktitle = {Tagungsband, 6th Embedded Software Engineering, Kongress 2013, 2. bis 6. Dezember 2013, Sindelfingen}, isbn = {978-3-8343-2408-5}, pages = {577 -- 585}, language = {de} } @inproceedings{SeidlKraemerMottok, author = {Seidl, M. and Kr{\"a}mer, Stefan and Mottok, J{\"u}rgen}, title = {Improving the reliability of an embedded real-time system by applying coded processing}, series = {4th Applied Research Conference, 5th July 2014, Ingolstadt}, booktitle = {4th Applied Research Conference, 5th July 2014, Ingolstadt}, publisher = {Shaker}, address = {Aachen}, isbn = {978-3-8440-2875-1}, pages = {70 -- 74}, language = {en} }