Institutszentrum Stuttgart der Fraunhofer-Gesellschaft IZS

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Öffentlicher Personen-Nahverkehr (ÖPNV) und Ansteckungsgefahr mit Sars-CoV-2

2022 , Will, Harald , Scherer, Christian , Stratbücker, Sebastian , Norrefeldt, Victor , Matheis, Christina , Herrmann, Tobias , Noethlichs, Ben , Heinrich, Joachim , Herbig, Britta , Salthammer, Tunga , Schreiner-Gruber, Sabrina , Eckhardt, Michael , Stiebritz, André , Jansson, Mattias , Schön, Martin

Diese Studie beleuchtet die Ansteckungsgefahr mit Sars-CoV-2 im Öffentlichen Personennahverkehr (ÖPNV). Methodisch werden hierbei drei Ansätze zur Klärung dieser Aufgabenstellung verfolgt: 1) Eine Literaturstudie wurde durchgeführt, um dokumentierte Ansteckungsfälle im ÖPNV zu finden sowie typische Betriebsparameter der Fahrzeuge zu identifizieren. 2) Im Rahmen von in-situ Messungen im ÖPNV wurden Luft- und Wischproben auf Sars-CoV-2 sowie auf die ubiquitär vorkommenden Humanen Adenoviren (HAdV) als Kontrollviren untersucht. Zusätzlich wurden die Verläufe der CO2-Konzentration im Innenraum gemessen, die in Kombination mit der festgestellten Belegung der Verkehrsmittel Rückschlüsse auf die Frischluftrate zulassen. In einigen Fahrzeugen wurde die Partikelkonzentration als Marker für die mögliche Aerosolbelastung gemessen. 3) Mit einem zonal unterteilten Simulationsmodell wurde eine Parameterstudie für die verschiedenen Verkehrsmittel durchgeführt, die die Ist-Situation beleuchtet sowie technische Nachrüstlösungen und Verhaltensanpassungen der Fahrgäste bewertet. Aus dem ÖPNV wurden hierbei exemplarisch die S-Bahn, U-Bahn, Stadtbus und Straßenbahn sowie der U-Bahnsteig untersucht. Bei den in-situ Messungen wurde in keiner Probe das SARS-CoV-2 Virus nachgewiesen und die Verläufe der CO2-Konzentrationsmessungen zeigen überwiegend einen Betrieb bei hygienisch unbedenklicher Luftqualität nach den in definierten Kriterien. Simulationen zeigen, dass das persönliche Verhalten wie das Tragen einer Maske und technische Lösungen wie die Umluftfilterung zu einer geringeren Exposition führen.

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An Agnostic Domain Specific Language for Implementing Attacks in an Automotive Use Case

2021 , Wolschke, Christian , Marksteiner, Stefan , Braun, Tobias , Wolf, Markus

This paper presents a Domain Specific Language (DSL) for generically describing cyber attacks, agnostic to specific system-under-test (SUT). The creation of the presented DSL is motivated by an automotive use case. The concepts of the DSL are generic such that attacks on arbitrary systems can be addressed. The ongoing trend to improve the user experience of vehicles with connected services implies an enhanced connectivity as well as remote accessible interface opens potential attack vectors. This might also impact safety and the proprietary nature of potential SUTs. Reusing tests of attack vectors to industrialize testing them on multiple SUTs mandates an abstraction mechanism to port an attack from one system to another. The DSL therefore generically describes attacks for the usage with a test case generator (and execution environment) also described in this paper. The latter use this description and a database with SUT-specific information to generate attack implementations for a multitude of different (automotive) SUTs.

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BiPS: A real-time-capable protocol framework for wireless networked control systems and its application

2019 , Engel, Markus , Kramer, Christopher , Braun, Tobias , Christmann, Dennis , Gotzhein, Reinhard

In wireless networked control systems (WNCS), sensors, controllers, and actuators exchange data to solve control tasks. Operation of WNCS usually occurs under real-time constraints, in particular regarding synchronicity of value sampling, transmission latencies, and packet losses. This calls for deterministic protocols as well as for real-time-capable implementations of these protocols. In this paper, we present the protocol framework BiPS (Black-burst integrated Protocol Stack), which provides real-time protocol and operating system functionalities, and its implementation on the Imote 2 hardware platform hosting the transceiver CC 2420. Furthermore, we present the application and deployment of BiPS in an industrial environment.

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Heat exchangers from metal-bonded La(Fe,Mn,Si)13Hx powder

2017 , Radulov, Iliya A. , Karpenkov, Dmitriy Y. , Specht, Marius , Braun, Tobias , Karpenkov, Alexey Y. , Skokov, Konstantin P. , Gutfleisch, Oliver

Hydrogenated La(Fe,Mn,Si)13-based alloys have an excellent magnetocaloric properties, but poor mechanical and chemical stability. This hinders their direct machining and implementation in an active magnetic regenerator (AMR). In this paper, we show how machinability and corrosion protection of the particles can be improved by a hot-dip coating. To avoid the loss of hydrogen during the coating process, a low melting temperature eutectic Bi-Sn-In alloy was selected as a metal binder. The coated particles were used to build a packed bed regenerator as an array of fixed particles, avoiding such negative effects as sedimentation, segregation, and channel deformation. Similarity theory, combined with unsteady heat transfer approach was applied in order to calculate the optimal operation frequency and to estimate the maximal cooling power of the magnetocaloric regenerators. Two different geometries of heat exchangers were theoretically compared: stacked flat plate/channel structure and packed bed of equidimensional spherical particles. It is shown that, operating at low frequency, the same amount of magnetocaloric material can expel bigger amount of heat, when formed as packed bed heat exchangers. The metal-bonded packed bed regenerator made from La(Fe,Mn,Si)13Hx powder was tested in a home-build versatile testing device in a magnetic field change of 10 kOe. The maximal achievable temperature span as a function of both parameters-hot end temperature and length of regenerator-was explored. The largest thermal span of 8 K was produced by the regenerator with 40 mm length.

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SaSeVAL: A Safety/Security-Aware Approach for Validation of Safety-Critical Systems

2021 , Wolschke, Christian , Sangchoolie, Behrooz , Simon, Jacob , Marksteiner, Stefan , Braun, Tobias , Hamazaryan, Hayk

Increasing communication and self-driving capabilities for road vehicles lead to threats which could potentially be exploited by attackers. Especially attacks leading to safety violations have to be identified to address them by appropriate measures. The impact of an attack depends on the threat exploited, potential countermeasures and the traffic situation. In order to identify such attacks and to use them for testing, we propose the systematic approach SaSeVAL for deriving attacks of autonomous vehicles.SaSeVAL is based on threats identification and safety-security analysis. The impact of automotive use cases to attacks is considered. The threat identification considers the attack interface of vehicles and classifies threat scenarios according to threat types, which are then mapped to attack types. The safety-security analysis identifies the necessary requirements which have to be tested based on the architecture of the system under test. It determines which safety impact a security violation may have, and in which traffic situations the highest impact is expected. Finally, the results of threat identification and safety-security analysis are used to describe attacks.The goal of SaSeVAL is to achieve safety validation of the vehicle w.r.t. security concerns. It traces safety goals to threats and to attacks explicitly. Hence, the coverage of safety concerns by security testing is assured. Two use cases of vehicle communication and autonomous driving are investigated to prove the applicability of the approach.

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Design and Qualification of Pr-Fe-Cu-B Alloys for the Additive Manufacturing of Permanent Magnets

2021 , Schäfer, Lukas , Skokov, Konstantin , Liu, Jianing , Maccari, Fernando , Braun, Tobias , Riegg, Stefan , Radulov, Iliya , Gassmann, Jürgen , Merschroth, Holger , Harbig, Jana , Weigold, Matthias , Gutfleisch, Oliver

The direct use of an advanced binder-free additive manufacturing technique, namely laser powder bed fusion (L-PBF), does not easily allow obtaining variously shaped, fully dense Nd-Fe-B magnets with high coercivity. The process inherently leads to the re-melting of the powder and appearance/disappearance of undesired/desired microstructural features responsible for low and large coercivity. In this work, the development of a useful microstructure responsible for high coercivity in Pr21Fe73.5Cu2B3.5 and Nd21Fe73.5Cu2B3.5 alloys and a possible way to produce fully dense permanent magnets via additive manufacturing processes is demonstrated using: (i) suction casting technique, which provides a high cooling rate and thus similar microstructures as in L-PBF but requires only very small amounts of powder; (ii) conventional L-PBF processing using kg of powder, and (iii) a subsequent annealing treatment that is similar to a conventional sintering treatment. The subsequent heat treatment is necessary to develop high coercivity by forming a novel microstructure: hard magnetic (Nd,Pr)2Fe14B grains embedded in a matrix of intermetallic (Nd,Pr)6Fe13Cu phase. Furthermore, it is demonstrated that Pr21Fe73.5Cu2B3.5 exhibits a higher coercivity than Nd21Fe73.5Cu2B3.5 because of a finer and more homogeneous grain size distribution of the Pr2Fe14B phase. The final L-PBF printed Pr21Fe73.5Cu2B3.5 samples provide a coercivity of 0.75 T.

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Predictive Runtime Simulation for Building Trust in Cooperative Autonomous Systems

2019 , Cioroaica, Emilia , Schneider, Daniel , Alzughbi, Hanna , Reich, Jan , Adler, Rasmus , Braun, Tobias

Future autonomous systems will also be cooperative systems. They will interact with each other, with traffic infrastructure, with cloud services and with other systems. In such an open ecosystem trust is of fundamental importance, because cooperation between systems is key for many innovation applications and services. Without an adequate notion of trust, as well as means to maintain and use it, the full potential of autonomous systems thus cannot be unlocked. In this paper, we discuss what constitutes trust in autonomous cooperative systems and sketch out a corresponding multifaceted notion of trust. We then go on to discuss a predictive runtime simulation approach as a building block for trust and elaborate on means to secure this approach.

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Ansatz zur methodischen Analyse und Absicherung des Funktionalkonzepts voll automatisierter Kraftfahrzeuge

2021 , Rauschenbach, Matthias , Kupjetz, Simon Matthias , Wolschke, Christian , Braun, Tobias

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Guideline for Architectural Safety, Security and Privacy Implementations Using Design Patterns: SECREDAS Approach

2021 , Marko, Nadja , Castella Triginer, Joaquim Maria , Striecks, Christoph , Braun, Tobias , Schwarz, Reinhard , Marksteiner, Stefan , Vasenev, Alexandr , Kemmerich, Jörg , Hamazaryan, Hayk , Shan, Lijun , Loiseaux, Claire

Vehicle systems engineering experiences new challenges with vehicle electrification, advanced driving systems, and connected vehicles. Modern architectural designs cope with an increasing number of functionalities integrated into complex Electric/Electronic (E/E) systems. Such complexity is extended, adding V2X (Vehicle-to-everything) communication systems, which provide remote communication services that collect, store, and manipulate confidential data. The impact on Safety, Security, and Privacy (SSP) of these new advanced technological systems requires the implementation of new processes during their development phase. Therefore, new product development strategies need to be implemented to integrate SSP mechanism across the entire product development lifecycle. The European H2020 ECSEL project SECREDAS proposes an innovative solution for Safety, Security and Privacy specifically for automated systems. The project outlines the shortcomings of existing SSP approaches and proposes its own approach to implementing SSP mechanism for the emerging technologies. This approach includes a reference architecture with SSP features implemented by a set of reusable Design Patterns (DPs) along with their associated technology elements. This guideline proposes rules for developing new architectural Safety, Security, and Privacy implementations in a product under development using Design Patterns.

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Production and properties of metal-bonded La(Fe,Mn,Si) 13Hx composite material

2017 , Radulov, Iliya A. , Karpenkov, Dmitriy Y. , Skokov, Konstantin P. , Karpenkov, Alexey Y. , Braun, Tobias , Brabänder, V. , Gottschall, Tino , Pabst, M. , Stoll, B. , Gutfleisch, Oliver

Due to their excellent magnetocaloric properties hydrogenated La(Fe,Mn,Si)13 are considered as promising and cost efficient materials for active magnetic regenerators operating near room temperature. However, due to their poor mechanical and chemical stability this alloys can not be directly implemented in a cooling machine. A solution of the problem is the production of a composite La(Fe,Mn,Si)13Hx magnetocaloric materials by using adhesive-bonding techniques similar to those used for production of polymer-bonded permanent magnets. Upon bonding one has to consider that the thermal stability of the polymer binder is rather low. Main disadvantage of a polymer-bonded composite is the fatigue due to the mechanical stress caused by the large magnetovolume effect in La(Fe,Mn,Si)13Hx. Our article reports on a new method and equipment to produce metal-bonded magnetocaloric material using the low melting eutectic Field's alloy as a binder. A comprehensive investigation of the magnetocaloric, mechanical, chemical and thermal transport properties of polymer-bonded and metal-bonded magnetocaloric material is presented.

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