@inproceedings{MuchaMottokKraemer, author = {Mucha, Matthias and Mottok, J{\"u}rgen and Kr{\"a}mer, Stefan}, title = {Estimation of Worst Case Response Time Boundaries in Multi-Core Real-Time Systems}, series = {2017 International Conference on Applied Electronics (AE), 5-6 Sept. 2017, Pilsen}, booktitle = {2017 International Conference on Applied Electronics (AE), 5-6 Sept. 2017, Pilsen}, publisher = {IEEE}, isbn = {978-80-261-0641-8}, issn = {1803-7232}, doi = {10.23919/ae.2017.8053598}, pages = {1 -- 6}, abstract = {We address a novel probabilistic approach to estimate the Worst Case Response Time boundaries of tasks. Multi-core real-time systems process tasks in parallel on two or more cores. Tasks in our contribution may preempt other tasks, block tasks with semaphores to access global shared resources, or migrate to another core. The depicted task behavior is random. The shape of collected response times of a task within a processing time is multimodal. Extreme Value approaches need unimodal response time distributions to estimate the Worst Case Response Time of tasks. The new proposed method derives a set of three task set shapes from the source task set. It is used to minimize the uncertainty of random task behavior by maximizing the coverage of possible Worst Case Response Times. The case study evaluates the new proposed estimation method by the use of dynamically generated random tasks with varying task properties.}, language = {en} } @article{DeBradaMottoketal., author = {De, Sangita and Brada, Premek and Mottok, J{\"u}rgen and Niklas, Michael}, title = {The Empirical Evaluation of Semantic Alignment Quality Metrics for Vehicle Domain Component Frameworks Interface Ontologies}, series = {FLAIRS 2021 : The 34th International FLAIRS Conference. Proceedings}, volume = {34}, journal = {FLAIRS 2021 : The 34th International FLAIRS Conference. Proceedings}, number = {1}, publisher = {LibraryPress@UF}, doi = {10.32473/flairs.v34i1.128512}, pages = {6}, abstract = {Semantic alignment of application software components' ontologies represents a great interest in vehicle application domains that manipulate heterogeneous overlapping knowledge application frameworks. In the past few years, with the growth in the novel vehicle service requirements such as autonomous driving, V2X (Vehicle-to-Vehicle communication) and many others, automotive application software component models are becoming increasingly collaborative with other qualified cross-enterprise industrial partners to accomplish these complex service requirements. The most daunting impediment to this cross-enterprise collaboration is semantic interoperability. For efficient services collaboration through cross-enterprise semantic interoperability between the vehicle application frameworks' software components, aligning the interface ontologies of these components by identifying the depth of semantic alignment relationships between the concepts of the interface ontologies is the major focus of this paper. In contrast to several existing ontology structural metrics, this work defines, evaluates and validates ontology metrics to measure the depth of semantic alignment between the vehicle domain software component frameworks' interface ontological models. To emphasize the substantial role of semantic alignment of software component frameworks' interface ontologies in semantic interoperability, a typical vehicle domain case study involving vehicle applications is considered for demonstration.}, language = {en} } @article{SchmidFritzMottok, author = {Schmid, Michael and Fritz, Florian and Mottok, J{\"u}rgen}, title = {Fine-grained parallelism framework with predictable work-stealing for real-time multiprocessor systems}, series = {Journal of Systems Architecture}, volume = {124}, journal = {Journal of Systems Architecture}, number = {March}, publisher = {Elsevier}, doi = {10.1016/j.sysarc.2022.102393}, abstract = {Lately, parallel task models have received much attention in the development of real-time multiprocessor systems, as they allow highly compute-intensive tasks to have shorter deadlines which is very much required in modern reactive systems. However, missing modularity and portability can make parallel programming a cumbersome endeavor. As a consequence, compute-intensive sectors in the desktop and server segment have relied on parallelism frameworks such as Intel Threading Building Blocks, Cilk and OpenMP. These parallelism frameworks, however, are optimized for decent average case performance and consequently, do not meet the strict requirements imposed by real-time systems. In this paper, we present a proof-of-concept parallelism framework which was implemented in particular for soft real-time systems and having tight timing and safety requirements of such critical systems in mind. The proposed runtime system implements static memory allocation in a work-stealing environment that conforms to the strict space and tight probabilistic time bounds of work-stealing schedulers. Furthermore, we evaluate the performance of this framework by conducting multiprogrammed benchmarks on a real-time embedded multicore architecture.}, language = {en} } @article{JosephSchummRummeletal., author = {Joseph, Saskia and Schumm, Michael and Rummel, Otmar and Soska, Alexander and Renschke, Michael and Mottok, J{\"u}rgen and Niemetz, Michael and Schroll-Decker, Irmgard}, title = {Teaching finite state machines with case method and role play}, series = {2014 IEEE Global Engineering Education Conference (EDUCON 2014) : Istanbul, Turkey, 3 - 5 April 2014}, journal = {2014 IEEE Global Engineering Education Conference (EDUCON 2014) : Istanbul, Turkey, 3 - 5 April 2014}, publisher = {IEEE}, doi = {10.1109/EduCon.2013.6530275}, pages = {1302 -- 1305}, 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. This paper will present a concept allowing to acquire competences by using Case Method and Role Play as instruments in several lectures of Software Engineering. By approaching the issue of competence acquisition on a technical as well as on an educational and social level, life-long learning is facilitated and supported.}, language = {en} } @inproceedings{PozzobonRennerMottoketal., author = {Pozzobon, Enrico and Renner, Sebastian and Mottok, J{\"u}rgen and Matoušek, V{\´a}clav}, title = {An optimized Bitsliced Masked Adder for ARM Thumb-2 Controllers}, series = {27th International Conference on Applied Electronics (AE): Sep 6, 2022 - Sep 7, 2022, Pilsen, Czech Republic}, booktitle = {27th International Conference on Applied Electronics (AE): Sep 6, 2022 - Sep 7, 2022, Pilsen, Czech Republic}, publisher = {IEEE}, doi = {10.1109/AE54730.2022.9919884}, pages = {4}, abstract = {The modular addition is used as a non-linear operation in ARX ciphers because it achieves the requirement of introducing non-linearity in a cryptographic primitive while only taking one clock cycle to execute on most modern architectures. This makes ARX ciphers especially fast in software implementations, but comes at the cost of making it harder to protect against side-channel information leakages using Boolean masking: the best known 2-shares masked adder for ARM Thumb micro-controllers takes 83 instructions to add two 32-bit numbers together. Our approach is to operate in bitsliced mode, performing 32 additions in parallel on a 32-bit microcontroller. We show that, even after taking into account the cost of bitslicing before and after the encryption, it is possible to achieve a higher throughput on the tested ciphers (CRAX and ChaCha20) when operating in bitsliced mode. Furthermore, we prove that no first-order information leakage is happening in either simulated power traces and power traces acquired from real hardware, after sufficient countermeasures are put into place to guard against pipeline leakages.}, language = {en} } @inproceedings{LaloSailerMottoketal., author = {Lalo, Erjola and Sailer, Andreas and Mottok, J{\"u}rgen and Siemers, Christian}, title = {Overhead-Aware Schedule Synthesis for Logical Execution Time (LET) in Automotive Systems}, series = {2022 IEEE 35th International System-on-Chip Conference (SOCC): 05-08 September 2022, Belfast, United Kingdom}, booktitle = {2022 IEEE 35th International System-on-Chip Conference (SOCC): 05-08 September 2022, Belfast, United Kingdom}, publisher = {IEEE}, isbn = {978-1-6654-5985-3}, doi = {10.1109/SOCC56010.2022.9908103}, pages = {1 -- 6}, abstract = {The Logical Execution Time (LET) has recently been integrated in multi-core automotive systems to ensure timing and dataflow determinism. Although buffering mechanisms are introduced to incorporate LET semantics, they do not guarantee that tasks are executed within their LET frames. In fact, LET and buffering semantics are violated if scheduling is not designed to execute all tasks within their LET frames and in a specific order. In this paper, we describe a scheduling synthesis technique for Fixed-Priority Scheduling (FPS) to achieve resource-efficient execution of LET systems. The proposed approach considers LET semantics, scheduling overheads, and delays caused by operating system operations and provides the possibility to optimize the schedule with respect to aspects like scheduling overheads. Our performance and feasibility evaluation shows that the proposed algorithm provides results in a reasonable amount of time for models of complex industrial applications. Thus, the integration of the proposed algorithm into an automated process is of high benefit to accelerate the development of vehicle applications.}, language = {en} } @inproceedings{FrauenschlaegerMottok, author = {Frauenschl{\"a}ger, Tobias and Mottok, J{\"u}rgen}, title = {Security-Gateway for SCADA-Systems in Critical Infrastructures}, series = {27th International Conference on Applied Electronics (AE): 06-07 September 2022, Pilsen, CZ}, booktitle = {27th International Conference on Applied Electronics (AE): 06-07 September 2022, Pilsen, CZ}, publisher = {IEEE}, doi = {10.1109/AE54730.2022.9920070}, pages = {6}, abstract = {Supervisory Control and Data Acquisition (SCADA) systems are used to control and monitor components within the energy grid, playing a significant role in the stability of the system. As a part of critical infrastructures, components in these systems have to fulfill a variety of different requirements regarding their dependability and must also undergo strict audit procedures in order to comply with all relevant standards. This results in a slow adoption of new functionalities. Due to the emerged threat of cyberattacks against critical infrastructures, extensive security measures are needed within these systems to protect them from adversaries and ensure a stable operation. In this work, a solution is proposed to integrate extensive security measures into current systems. By deploying additional security-gateways into the communication path between two nodes, security features can be integrated transparently for the existing components. The developed security-gateway is compliant to all regulatory requirements and features an internal architecture based on the separation-of-concerns principle to increase its security and longevity. The viability of the proposed solution has been verified in different scenarios, consisting of realistic field tests, security penetration tests and various performance evaluations.}, language = {en} } @inproceedings{SchmidMottok, author = {Schmid, Michael and Mottok, J{\"u}rgen}, title = {Investigation of Scheduling Algorithms for DAG. Tasks through Simulations}, series = {ERTS 2022, 11th European Congress Embedded Real Time Systems: 1-2 June, Toulouse, France}, booktitle = {ERTS 2022, 11th European Congress Embedded Real Time Systems: 1-2 June, Toulouse, France}, pages = {9}, abstract = {In the real-time systems sector, various task models and corresponding tests exist to model and verify the schedulability of task sets on the system at hand. While those models and schedulability tests have intensively been studied from a theoretical point of view, it is hard to ma e use of them to compare the actual execution behavior of scheduling algorithms on a real system. In contrast to schedulability tests, simulators can help to investigate the performance of specific scheduling algorithms. One of the most generalized task models to describe parallel tasks is the Directed Acyclic Graph model that allows to represent tasks as a series of subtasks that depict the potentially parallel computations and precedence constraints that denote the order in which the subtasks are allowed to execute. In this paper, we investigate various scheduling algorithms for the Directed Acyclic Graph model. For that, we first recapitulate the examined scheduling algorithms in detail and point out relevant differences. Subsequently, we present the evaluation of different global and federated scheduling algorithms using fine-grained parallel tasks. To this end, we generate random Directed Acyclic Graph tasks and simulate their execution on multiprocessor systems using scheduling algorithms such as global rate-monotonic and semi-federated scheduling as well as global scheduling policies using the thread pool model.}, language = {en} } @inproceedings{GrabingerHauserMottok, author = {Grabinger, Lisa and Hauser, Florian and Mottok, J{\"u}rgen}, title = {Accessing the Presentation of Causal Graphs and an Application of Gestalt Principles with Eye Tracking}, series = {2022 IEEE International Conference on Software Analysis, Evolution and Reengineering (SANER 2022), 1st Workshop on Advances in Human-Centric Experiments in Software Engineering (HUMAN 2022): 15-18 March 2022, Honolulu, HI, USA}, booktitle = {2022 IEEE International Conference on Software Analysis, Evolution and Reengineering (SANER 2022), 1st Workshop on Advances in Human-Centric Experiments in Software Engineering (HUMAN 2022): 15-18 March 2022, Honolulu, HI, USA}, publisher = {IEEE}, doi = {10.1109/SANER53432.2022.00153}, pages = {1278 -- 1285}, abstract = {The discipline of causal inference uses so-called causal graphs to model cause and effect relations of random variables. As those graphs only encode a relation structure there is no hard rule concerning their alignment. The present paper presents a study with the aim of working out the optimal alignment of causal graphs with respect to comprehensibility and interestingness. In addition, the study examines whether the central gestalt principles of psychology apply for causal graphs. Data from 29 participants is acquired by triangulating eye tracking with a questionnaire. The results of the study suggest that causal graphs should be aligned downwards. Moreover, the gestalt principles proximity, similarity and closure are shown to hold true for causal graphs.}, language = {en} } @misc{RennerPozzobonMottok, author = {Renner, Sebastian and Pozzobon, Enrico and Mottok, J{\"u}rgen}, title = {3rd Round Ciphers Evaluation on Microcontrollers}, series = {Lightweight Cryptography Workshop (virtual): May 9-11 2022}, journal = {Lightweight Cryptography Workshop (virtual): May 9-11 2022}, publisher = {National Institute of Standards and Technology (NIST)}, address = {Gaithersburg}, language = {en} } @inproceedings{DeNiklasRooneyetal., author = {De, Sangita and Niklas, Michael and Rooney, Brian and Mottok, J{\"u}rgen and Brada, Premek}, title = {Towards Semantic model-to-model Mapping of Cross-Domain Component Interfaces for Interoperability of Vehicle Applications : An Approach towards Synergy Exploration}, series = {MDE4IoT \& ModComp 2019: Model-Driven Engineering for the Internet of Things (MDE4IoT) \& Interplay of Model-Driven and Component-Based Software Engineering (ModComp); joint proceedings of the Workshop on Model-Driven Engineering for the Internet of Things (MDE4IoT) \& of the Workshop on Interplay of Model-Driven and Component-Based Software Engineering (ModComp); co-located with the IEEE/ACM 22nd International Conference on Model Driven Engineering Languages and Systems (MODELS 2019), Munich, Germany, September 15 and 17, 2019}, booktitle = {MDE4IoT \& ModComp 2019: Model-Driven Engineering for the Internet of Things (MDE4IoT) \& Interplay of Model-Driven and Component-Based Software Engineering (ModComp); joint proceedings of the Workshop on Model-Driven Engineering for the Internet of Things (MDE4IoT) \& of the Workshop on Interplay of Model-Driven and Component-Based Software Engineering (ModComp); co-located with the IEEE/ACM 22nd International Conference on Model Driven Engineering Languages and Systems (MODELS 2019), Munich, Germany, September 15 and 17, 2019}, publisher = {RWTH Aachen}, address = {Aachen}, doi = {10.13140/RG.2.2.28765.15840}, abstract = {With the increase in demand of services in the automotive industry, automotive enterprises prefer to collaborate with other qualified cross-domain partners to provide complex automotive functions (or services), such as autonomous driving, OTA (Over The Air) vehicle update, V2X (Vehicle-to-Vehicle communication), etc. One key element in cross-domain enterprise collaboration is the mutual agreement between interfaces of software components. In this context, model-to-model mappings of software component models of heterogeneous frameworks for automotive services and to explore the synergies in their interface semantics, have become an essential factor in improving the interoperability among the automotive and other cross-domain enterprises. However, one of the challenges in achieving cross-domain component interface model-to-model mappings at an application level lies in detecting the interface semantics and the semantic relations that are conveyed in different component models in different frameworks. This paper addresses this challenge using a Model Driven Architecture (MDA) based analytical approach to explore interface semantic synergies in the cross-domain component meta-models that are used for automotive services. The approach applies manual semantic checking measurements at an application interface level to understand the meanings and relations between the different meta-model entities of cross-domain framework software components. In this research, we attempt to ensure that interface description models of software components from heterogeneous frameworks can be compared, correlated and re-used for automotive services based on semantic synergies. We have demonstrated our approach using component meta-models from cross-domain enterprises, that are used for the automotive application domain.}, language = {en} } @inproceedings{RennerPozzobonMottok, author = {Renner, Sebastian and Pozzobon, Enrico and Mottok, J{\"u}rgen}, title = {The Final Round: Benchmarking NIST LWC Ciphers on Microcontrollers}, series = {Attacks and Defenses for the Internet-of-Things, 5th International Workshop, ADIoT 2022: Copenhagen, Denmark, September 30, 2022, Revised Selected Papers}, booktitle = {Attacks and Defenses for the Internet-of-Things, 5th International Workshop, ADIoT 2022: Copenhagen, Denmark, September 30, 2022, Revised Selected Papers}, editor = {Li, Wenjuan and Furnell, Steven and Meng, Weizhi}, publisher = {Springer Nature}, address = {Cham}, isbn = {978-3-031-21311-3}, doi = {10.1007/978-3-031-21311-3_1}, pages = {1 -- 20}, abstract = {In this work, we present our benchmarking results for the ten finalist ciphers of the Lightweight Cryptography (LWC) project initiated by National Institute of Standards and Technology (NIST). We evaluate the speed and code size of various software implementations on five different platforms featuring four different architectures. Moreover, we benchmark the dynamic memory utilization of the remaining NIST LWC algorithms on one 32-bit ARM controller. We describe our test cases and methodology and provide some information regarding the design and properties of the finalists before showing and discussing our results. Altogether, we evaluated almost 300 implementations of the 3rd round candidates and pick the most appropriate and best (primary) implementation of each cipher for our comparisons. We include a variant of AES-GCM in our benchmarking in order to be able to compare the state-of-the-art to the novel LWC ciphers. Our research gives an overview over the performance of the latest software implementations of the NIST LWC finalists and shows under which circumstances which candidate is performing the best in our individual test cases. Additionally, we make all benchmarking results, the code for our test framework and every tested implementation available to the public to ensure a transparent testing process.}, language = {en} } @inproceedings{RennerPozzobonMottok, author = {Renner, Sebastian and Pozzobon, Enrico and Mottok, J{\"u}rgen}, title = {Evolving a Boolean Masked Adder Using Neuroevolution}, series = {Attacks and Defenses for the Internet-of-Things, 5th International Workshop, ADIoT 2022: Copenhagen, Denmark, September 30, 2022, Revised Selected Papers}, booktitle = {Attacks and Defenses for the Internet-of-Things, 5th International Workshop, ADIoT 2022: Copenhagen, Denmark, September 30, 2022, Revised Selected Papers}, editor = {Li, Wenjuan and Furnell, Steven and Meng, Weizhi}, publisher = {Springer Nature}, address = {Cham}, isbn = {978-3-031-21310-6}, doi = {10.1007/978-3-031-21311-3_2}, pages = {21 -- 40}, abstract = {The modular addition is a popular building block when designing lightweight ciphers. While algorithms mainly based on the addition can reach very high performance, masking their implementations results in a huge penalty. Since efficient protection against side-channel attacks is a requirement in lots of use cases, we focus on optimizing the Boolean masking of the modular addition. Contrary to recent related work, we target evolving a masked full adder instead of parts of a parallel prefix adder. We study how techniques typically found in neural network evolution and genetic algorithms can be adapted in order to help in evolving an efficiently masked adder. We customize a well-known neuroevolution algorithm, develop an optimized masked adder with our new approach and implement the ChaCha20 cipher on an ARM Cortex-M3 controller. We compare the performance of the protected neuroevolved implementation to solutions found by traditional search methods. Moreover, the leakage of our new solution is validated by a t-test conducted with a leakage simulator. We present under which circumstances our masked implementation outperforms related work and prove the feasibility of successfully using neuroevolution when searching for complex Boolean networks.}, language = {en} } @inproceedings{DeMottokBrada, author = {De, Sangita and Mottok, J{\"u}rgen and Brada, Premek}, title = {Evaluation of Semantic Interoperability of Automotive Service API Models Based on Metamodels Similarity Metrics Using a Semi-automated Approach}, series = {iCETiC 2022 : 5th International Conference on Emerging Technologies in Computing 2022: Aug 15, 2022 - Aug 16, 2022, Chester, UK}, booktitle = {iCETiC 2022 : 5th International Conference on Emerging Technologies in Computing 2022: Aug 15, 2022 - Aug 16, 2022, Chester, UK}, editor = {Miraz, M.H. and Southall, G. and Ali, Maaruf and Ware, A.}, publisher = {Springer}, address = {Cham}, doi = {10.1007/978-3-031-25161-0_2}, pages = {14 -- 28}, abstract = {In recent years, mapping of application software components' ontologies semantically emerged as a big research challenge in automotive application domain that manipulates several cross-enterprise synergy knowledge application frameworks. The same knowledge formalized by different experts in different vehicle application frameworks leads to heterogeneous representations of components' interface data. Consequently, this causes the most daunting impediment in semantic interoperability between the service components in cooperative automotive systems. From a modeling perspective, in the absence of standardized domain-based unified modeling techniques, the orchestration and resolution of semantic data interoperability between various vehicle application frameworks' components' interface models remain a challenge. However, this challenge could be addressed using ontological metamodeling by specifying semantic associations between components' interface model concepts based on the domain knowledge. Apart from the semantic mapping of interface ontological metamodels, this work also defines quality metrics to determine the degree of semantic alignment achieved between the various interface ontologies. Additionally, to reduce development time and cost towards semantic interoperability, this work proposes a semi-automated plugin tool for the applicability of the evaluated quality metrics to semantic mapping of real-world components' interface models.}, language = {en} } @inproceedings{GrabingerHauserMottok, author = {Grabinger, Lisa and Hauser, Florian and Mottok, J{\"u}rgen}, title = {Evaluating Graph-based Modeling Languages}, series = {Proceedings of the 5th European Conference on Software Engineering Education, Seeon/Germany, June 19 - 21, 2023}, booktitle = {Proceedings of the 5th European Conference on Software Engineering Education, Seeon/Germany, June 19 - 21, 2023}, publisher = {ACM}, isbn = {978-1-4503-9956-2}, doi = {10.1145/3593663.3593664}, pages = {120 -- 129}, abstract = {As humans, we tend to use models to describe reality. Modeling languages provide the formal frameworks for creating such models. Usually, the graphical design of individual model elements is based on subjective decisions; their suitability is determined at most by the prevalence of the modeling language. With other words: there is no objective way to compare different designs of model elements. The present paper addresses this issue: it introduces a systematic approach for evaluating the elements of graph-based modeling languages comprising 14 criteria - derived from standards, usability analyses, or the design theories 'Physics of Notations' and 'Cognitive Dimensions of Notations'. The criteria come with measurement procedures and evaluation schemes based on reasoning, eye tracking, and questioning. The developed approach is demonstrated with a specific use case: three distinct sets of node elements for causal graphs are evaluated in an eye tracking study with 41 subjects.}, language = {en} } @inproceedings{HauserGrabingerMottok, author = {Hauser, Florian and Grabinger, Lisa and Mottok, J{\"u}rgen}, title = {Something Short Gets Even Shorter: Adapting the LIST-K for the Use in an Online Learning Management System}, series = {Proceedings of the 5th European Conference on Software Engineering Education, Seeon/Germany, June 19 - 21, 2023}, booktitle = {Proceedings of the 5th European Conference on Software Engineering Education, Seeon/Germany, June 19 - 21, 2023}, publisher = {ACM}, isbn = {978-1-4503-9956-2}, doi = {10.1145/3593663.3593684}, pages = {65 -- 72}, abstract = {This study examines how Klingsieck's LIST-K questionnaire [22] can be shortened and adapted to the requirements of an online learning management system. In a study with 213 participants, the questionnaire is subjected to an exploitative factor analysis. In a next step, the results are evaluated in terms of their reliability. This process creates a modified factor structure for the LIST-K, comprising a total of eight factors. The reliability of the modified questionnaire is at an α of .770. The shortened version of the LIST-K questionnaire is currently being used on an experimental basis in different courses.}, language = {en} } @article{DePremekMottok, author = {De, Sangita and Premek, Brada and Mottok, J{\"u}rgen}, title = {Derivation of Optimized Threshold of Semantic Alignment Metrics for Intepretation of Interoperability and Reusability of Cross-enterprise Vehicle Service Interface Models}, series = {Informatica}, volume = {47}, journal = {Informatica}, number = {7}, publisher = {Slovenian Society Informatika}, issn = {0350-5596}, doi = {10.31449/inf.v47i7.4739}, abstract = {Over the past decade, cars have turned gradually into real cyber physical systems. The collaboration of services between the service-oriented, cross-enterprise vehicle application frameworks has increased to generate novel, smart and complicated vehicle services. Consequently, from an interoperability perspective, semantically mapping of vehicle service component's interface ontological models emerged as a big research interest in automotive application domain that manipulates several cross-enterprise synergy knowledge applications frameworks. The ontological metamodeling lays the foundation for building semantic bridge and exploring semantic associations between service components' interface models based on the domain knowledge for semantic interoperability. Also, several semantic quality metrics has been defined over time for the vehicle service interface ontological metamodels. The empirically evaluated values of these metrics can be used to assess progress in cross-enterprise interoperability between the service and the clients' APIs ontological models in vehicle domain. Despite potential benefits of semantic alignment quality metrics, the effective use of these metrics for vehicle service interface ontologies have proven elusive. Yes, such metrics can be used successfully for quantification, but then they mostly fail to provide adequate annotations in subsequent decision-making in the direction of semantic interoperability and reusability. The effective use of ontology semantic alignment quality metrics is basically hindered in the absence of the meaningful thresholds. In fact, the absence of an effective and meaningful threshold for the semantic similarity measure between various vehicle service interface ontological metamodels, motivates this research work which not only proposes a design approach to an optimized threshold for the semantic similarity metrics but also applies this threshold on few defined semantic alignment quality metrics. This paper also uses a real-world vehicle domain industrial case study to illustrate the design approach.}, language = {en} } @unpublished{LinzMottok, author = {Linz, Tilo and Mottok, J{\"u}rgen}, title = {Application of Causal Models in Scenario-based Testing}, doi = {10.13140/RG.2.2.34160.06402}, abstract = {This paper presents a new methodology for scenario-based testing of automated driving functions in the context of ISO 21448 (safety of the target function). By using structural causal models (SCMs), the evaluation process of highly automated vehicle systems is to be improved, thus increasing their safety and reliability. Using SCMs, the presented methodology systematically analyzes causal relationships between various risk factors of the investigated system and its operating environment and automatically identifies potential parameter combinations that influence system safety. This approach makes it possible to safeguard automated driving functions, such as an emergency brake assistant, by determining foreseeable risks and providing them as test parameters for relevant scenarios. The HolmeS3 approach combines expert knowledge with probabilistic data analysis to develop robust causal models that can be validated through both simulation and real-world testing. The use of causal inference enables the generation of critical test cases, known as "edge and corner cases", which are essential for testing vehicle systems under investigation. This focused testing approach helps to limit the test case explosion that occurs with conventional approaches by specifically identifying highly relevant parameter combinations that potentially (negatively) influence system performance. The methodology presented, which was developed as part of the HolmeS3 R\&D project, offers transparency, comparability, explainability and traceability in the modeling and testing processes. It supports compliance with the ISO 21448 standard and lays the foundation for the causality-driven development of safe and reliable automotive technology. The project's tools and methods can be applied beyond the automotive sector to all cyber-physical systems that require rigorous safety validation.}, language = {en} } @inproceedings{FrauenschlaegerMottok, author = {Frauenschl{\"a}ger, Tobias and Mottok, J{\"u}rgen}, title = {Problems and New Approaches for Crypto-Agility in Operational Technology}, series = {12th European Congress Embedded Real Time Systems (ERTS 2024), 11-12 June 2024, Toulouse, France}, booktitle = {12th European Congress Embedded Real Time Systems (ERTS 2024), 11-12 June 2024, Toulouse, France}, abstract = {In recent years, cybersecurity has also become relevant for Operational Technology (OT). Critical systems like industrial automation systems or transportation systems are faced with new threats, and therefore require the implementation of thorough security measures. Regulations further mandate the deployment and regular verification of these security measures. However, OT systems differ from well-known systems of classic Information Technology (IT), such as mission times spanning decades, infrequent updates only during on-site maintenance, or diverse devices with varying support for security measures. The growing field of crypto-agility examines approaches to integrate security measures in an agile and flexible way, making updates easier and, therefore, encouraging a more frequent deployment of them. This paper contributes to this research field in the context of secure communication in two ways. We first examine the current state of crypto-agility by providing an overview of existing measures for OT systems. Then, we propose a new architecture concept with different deployment approaches to integrate security measures in a crypto-agile way. Based on a security library with a generic interface and a flexible proxy application, our architecture is capable of securing both new OT systems and existing ones via retrofit.}, language = {en} } @inproceedings{SchwindFrauenschlaegerMottok, author = {Schwind, Philipp and Frauenschl{\"a}ger, Tobias and Mottok, J{\"u}rgen}, title = {Implementation of a Bump-in-the-Wire Security Gateway}, series = {Proceedings of the 12th Prague Embedded Systems Workshop, June 27 - 29, 2024, Horoměřice, Czech Republic}, booktitle = {Proceedings of the 12th Prague Embedded Systems Workshop, June 27 - 29, 2024, Horoměřice, Czech Republic}, isbn = {978-80-01-07303-2}, pages = {26 -- 35}, abstract = {In the face of escalating cyber threats, the integration of Operational Technology (OT) with Information Technology (IT) systems presents heightened vulnerabilities to critical infrastructures. This paper focuses on the need for cybersecurity, showcasing the design and implementation of a security gateway to achieve bump-in-the-wire security between two units to be protected (assets). For that, each asset is assigned one security module that safeguards its communication paths. To ease bump-in-the-wire capability, the communication between the asset and the security-gateway must be stateless and operate on OSI layer 2. This is necessary to safeguard the whole communication bandwidth, regardless of the used protocols. For this objective, Linux-based packet sockets are used. An encrypted tunnel is established between two security gateways using the Datagram Transport Layer Security (DTLS) protocol. The results show that the implemented solution is capable of securing the asset's network traffic without the need of any modifications.}, language = {en} } @inproceedings{HornFrauenschlaegerMottok, author = {Horn, Luca and Frauenschl{\"a}ger, Tobias and Mottok, J{\"u}rgen}, title = {Integration and Evaluation of Different FPGA based Hardware Accelerators for the AES Algorithm in the TLS Protocol to be Used in Critical Automation Systems}, series = {4. Symposium Elektronik und Systemintegration, Tagungsband: Symposium am 17. April 2024 Hochschule Landshut}, booktitle = {4. Symposium Elektronik und Systemintegration, Tagungsband: Symposium am 17. April 2024 Hochschule Landshut}, publisher = {Hochschule Landshut}, address = {Landshut}, isbn = {978-3-9818439-9-6}, pages = {18 -- 27}, abstract = {This thesis addresses the challenges of hardware-assisted cryptography in the context of automation systems in critical infrastructures. While hardware accelerators enhance cryptographic calculations in both performance and security, their permanence poses issues in adapting to evolving security concerns. To overcome this problem, we integrated and evaluated a hardware accelerator for the AES algorithm on an FPGA within a TLS application, comparing its performance with other accelerators. Employing a hybrid FPGA-CPU processor system, this setup achieves over 800 Mbit/s data rates, showcasing a more than 27 times acceleration in TLS transmissions compared to purely software-based solutions. The FPGA's flexibility and upgradability therefore make it an ideal platform for critical infrastructure, ensuring longevity and superior acceleration in TLS data transfers.}, language = {en} } @inproceedings{HauserGrabingerMottoketal., author = {Hauser, Florian and Grabinger, Lisa and Mottok, J{\"u}rgen and Gruber, Hans}, title = {Visual Expertise in Code Reviews: Using Holistic Models of Image Perception to Analyze and Interpret Eye Movements}, series = {ETRA '23: 2023 Symposium on Eye Tracking Research and Applications, Tubingen Germany 30 May 2023- 2 June 2023}, booktitle = {ETRA '23: 2023 Symposium on Eye Tracking Research and Applications, Tubingen Germany 30 May 2023- 2 June 2023}, publisher = {ACM}, doi = {10.1145/3588015.3589189}, pages = {1 -- 7}, abstract = {This study uses holistic models of image perception to analyze and interpret eye movements during a code review. 23 participants (15 novices and 8 experts) take part in the experiment. The subjects' task is to review six short code examples in C programming language and identify possible errors. During the experiment, their eye movements are recorded by an SMI 250 REDmobile. Additional data is collected through questionnaires and retrospective interviews. The results implicate that holistic models of image perception provide a suitable theoretical background for the analysis and interpretation of eye movements during code reviews. The assumptions of these models are particularly evident for expert programmers. Their approach can be divided into different phases with characteristic eye movement patterns. It is best described as switching between scans of the code example (global viewing) and the detailed examination of errors (focal viewing).}, language = {en} }