Christian Dietrich

Technische Universität Braunschweig

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Daniel Lohmann

Leibniz University Hannover

Jürgen Janek

University of Giessen

Wolfgang G. Zeier

University of Münster

Christian Rossow

Helmholtz Center for Information Security

Martin Hoffmann

Ruhr University Bochum

Wolfgang Schröder‐Preikschat

Friedrich-Alexander-Universität Erlangen-Nürnberg

Norbert Pohlmann

FH Aachen

Ken Jacobson

University of North Carolina at Chapel Hill

Stefan J. Sedlmaier

BMW Group (Germany)

Henrik Eickhoff

Technical University of Munich

Cooperative Institutions

Technical University of Munich

Friedrich-Alexander-Universität Erlangen-Nürnberg

University of Giessen

Leibniz University Hannover

Ludwig-Maximilians-Universität München

Giessen School of Theology

Technical University of Darmstadt

Karlsruhe Institute of Technology

Max Planck Society

Heidelberg University

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Whole-system worst-case energy-consumption analysis for energy-constrained real-time systems

Euromicro Conference on Real-Time Systems (2018)

Peter Wägemann Christian Dietrich Tobias Distler Peter Ulbrich Wolfgang Schröder‐Preikschat

Although internal devices (e.g., memory, timers) and external devices (e.g., transceivers, sensors) significantly contribute to the energy consumption of an embedded real-time system, their impact on the worst-case response energy consumption (WCRE) of tasks is usually not adequately taken into account. Most WCRE analysis techniques, for example, only focus on the processor and therefore do not consider the energy consumption of other hardware units. Apart from that, the typical approach for dealing with devices is to assume that all of them are always activated, which leads to high WCRE overestimations in the general case where a system switches off the devices that are currently not needed in order to minimize energy consumption. In this paper, we present SysWCEC, an approach that addresses these problems by enabling static WCRE analysis for entire real-time systems, including internal as well as external devices. For this purpose, SysWCEC introduces a novel abstraction, the power-state-transition graph, which contains information about the worst-case energy consumption of all possible execution paths. To construct the graph, SysWCEC decomposes the analyzed real-time system into blocks during which the set of active devices in the system does not change and is consequently able to precisely handle devices being dynamically activated or deactivated.

Abstraction

10.4230/lipics.ecrts.2018.24

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Citations (18)

ACTOR: Accelerating Fault Injection Campaigns Using Timeout Detection Based on Autocorrelation

Lecture notes in computer science (2022)

Tim-Marek Thomas Christian Dietrich Oskar Pusz Daniel Lohmann

Time-out

Fault injection

Pruning

10.1007/978-3-031-14835-4_17

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Citations (1)

Lithium Phosphidogermanates α- and β-Li₈GeP₄—A Novel Compound Class with Mixed Li⁺ Ionic and Electronic Conductivity

Chemistry of Materials (2018)

Henrik Eickhoff Stefan Strangmüller Wilhelm Klein Holger Kirchhain Christian Dietrich

To utilize all-solid-state batteries as high power and energy density energy storage devices it is necessary to improve the current electrolyte materials and the cell architecture. In this work, we present α- and β-Li8GeP4 as potential compounds for the use in cathode composites of solid-state batteries because of their ability to conduct both Li+ ion and electrons. Each polymorph was synthesized via mechanical alloying of the elements and subsequent annealing. Structural analysis of α- and β-Li8GeP4 via X-ray diffraction reveals isolated [GeP4]8– tetrahedra. α-Li8GeP4 (Pa3̅) and β-Li8GeP4 (P4̅3n) are isotypic with Li8SiP4 and Li8SnP4, respectively. The lithium ion mobility indicated by partially filled octahedral voids was investigated by temperature-dependent nuclear magnetic resonance and electrochemical impedance spectroscopy and reveals low activation energies for lithium hopping in the range from 34 and 42 kJ mol–1 as well as high ionic conductivities of up to 8 × 10–5 S cm–1 and electronic conductivities of up to 4 × 10–7 S cm–1 at 293 K. These results combine a new substance class with a systematic synthesis approach for materials with high ionic carrier densities.

10.1021/acs.chemmater.8b02759

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Citations (36)

Beyond early development: observing zebrafish over 6 weeks with hybrid optical and optoacoustic imaging

bioRxiv (Cold Spring Harbor Laboratory) (2019)

Paul Vetschera Benno Koberstein‐Schwarz Tobias Schmitt‐Manderbach Christian Dietrich Wibke Hellmich

Abstract Zebrafish animal models have traditionally been used in developmental biology studies but have recently become promising models of cancer, tissue regeneration and metabolic disorders, as well as efficient platforms for functional genomics and phenotype-based drug discovery. Most studies of zebrafish have examined only the embryonic or larval stages of development, yet many questions in developmental biology and biomedicine require analysis of adults, when zebrafish are large and opaque. Conventional microscopy methods are highly sensitive to light scattering and therefore cannot be applied to zebrafish older than a few weeks. We describe a novel multi-modality system that can observe zebrafish from the larval stage to adulthood. Using a hybrid platform for concurrent selective plane illumination microscopy (SPIM) and optoacoustic mesoscopy we show continuous imaging of fish growth over 47 days of development at a similar object size-to-resolution ratio. Using multiple wavelength illumination over the visible and short-wavelength infrared regions, we reveal that the optoacoustic method can follow GFP-based contrast used in SPIM, enabling molecular imaging interrogation in adult fish. Moreover we optoacoustically reveal many other features of zebrafish based on optical contrast not present in SPIM, including contrast from endogenous blood, water and lipids. The hybrid method presented can extend optical imaging to adult zebrafish employed as model systems for studying long-term processes in development, cancer, diabetes and other disorders.

Developmental Biology

10.1101/586933

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Citations (3)

Biofunctionalized Membranes on Solid Surfaces

Robert Tampé Christian Dietrich Stefan Gritsch G. Elender Lutz Schmitt

Source

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Citations (9)

Whole-System WCEC Analysis for Energy-Constrained Real-Time Systems (Artifact)

Peter Wägemann Christian Dietrich Tobias Distler Peter Ulbrich Wolfgang Schröder‐Preikschat

Although internal devices (e.g., memory, timers) and external devices (e.g., sensors, transceivers) significantly contribute to the energy consumption of an embedded real-time system, their impact on the worst-case response energy consumption (WCRE) of tasks is usually not adequately taken into account. Most WCRE analysis techniques only focus on the processor and neglect the energy consumption of other hardware units that are temporarily activated and deactivated in the system. To solve the problem of system-wide energy-consumption analysis, we present SysWCEC, an approach that addresses these problems by enabling static WCRE analysis for entire real-time systems, including internal as well as external devices. For this purpose, SysWCEC introduces a novel abstraction, the power-state--transition graph, which contains information about the worst-case energy consumption of all possible execution paths. To construct the graph, SysWCEC decomposes the analyzed real-time system into blocks during which the set of active devices in the system does not change and is consequently able to precisely handle devices being dynamically activated or deactivated. In this artifact evaluation, which accompanies our related conference paper, we present easy to reproduce WCRE analyses with the SysWCEC framework using several benchmarks. The artifact comprises the generation of the power-state--transition graph from a given benchmark system and the formulation of an integer linear program whose solution eventually yields safe WCRE bounds.

Benchmark (surveying)

Abstraction

10.4230/darts.4.2.7

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Citations (0)

A Practitioner's Guide to Software-Based Soft-Error Mitigation Using AN-Codes

Martin Hoffmann Peter Ulbrich Christian Dietrich Horst Schirmeier Daniel Lohmann

Arithmetic error coding schemes (AN codes) are a well known and effective technique for soft error mitigation. Although coding theory being a rich area of mathematics, their implementation seems to be fairly easy. However, compliance with the theory can be lost easily while moving towards an actual implementation - finally jeopardizing the aspired fault-tolerance characteristics. In this paper, we present our experiences and lessons learned from implementing AN codes in the Cored dependable voter. We focus on the challenges and pitfalls in the transition from maths to machine code for a binary computer from a systems perspective. Our results show, that practical misconceptions (such as the use of prime numbers) and architecture-dependent implementation glitches occur on every stage of this transition. We identify typical pitfalls and describe practical measures to find and resolve them. Our measures eliminate all remaining SDCs in the Cored voter, which is validated by an extensive fault-injection campaign that covers 100 percent of the fault space for 1-bit and 2-bit errors.

Soft error

10.1109/hase.2014.14

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Citations (20)

Cloud-Native Database Systems and Unikernels: Reimagining OS Abstractions for Modern Hardware

Proceedings of the VLDB Endowment (2024)

Viktor Leis Christian Dietrich

This paper explores the intersection of operating systems and database systems, focusing on the potential of specialized kernels for cloud-native database systems. Although the idea of custom, DBMS-optimized OS kernels is old, it is largely unrealized due to the demands of hardware compatibility and the reluctance of users to install specialized operating systems. However, the cloud and the database-as-a-service model make custom OS kernels realistic for the first time. Among specialized OS kernel architectures, unikernels stand out for relying on a single address space, eliminating the need for costly process isolation that is provided by general-purpose operating systems. They offer benefits such as the elimination of system call overhead, direct access to hardware, and reduced complexity. Beyond these immediate advantages, unikernels offer a unique opportunity: the possibility to revisit dated POSIX APIs. By allowing direct interaction with modern hardware primitives, unikernels pave the way for the development of novel abstractions that are not confined to the limitations of older APIs, opening doors to a new era of co-designed, high-performance cloud-native data processing systems and OS kernels.

System call

POSIX

10.14778/3659437.3659462

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Citations (2)

Linux variability anomalies: What causes them and how do they get fixed?

Sarah Nadi Christian Dietrich Reinhard Tartler Richard C. Holt Daniel Lohmann

The Linux kernel is one of the largest configurable open source software systems implementing static variability. In Linux, variability is scattered over three different artifacts: source code files, Kconfig files, and Makefiles. Previous work detected inconsistencies between these artifacts that led to anomalies in the intended variability of Linux. We call these variability anomalies. However, there has been no work done to analyze how these variability anomalies are introduced in the first place, and how they get fixed. In this work, we provide an analysis of the causes and fixes of variability anomalies in Linux. We first perform an exploratory case study that uses an existing set of patches which solve variability anomalies to identify patterns for their causes. The observations we make from this dataset allow us to develop four research questions which we then answer in a confirmatory case study on the scope of the whole Linux kernel. We show that variability anomalies exist for several releases in the kernel before they get fixed, and that contrary to our initial suspicion, typos in feature names do not commonly cause these anomalies. Our results show that variability anomalies are often introduced through incomplete patches that change Kconfig definitions without properly propagating these changes to the rest of the system. Anomalies are then commonly fixed through changes to the code rather than to Kconfig files.

Kernel (algebra)

Code (set theory)

Scope (computer science)

10.1109/msr.2013.6624017

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Citations (19)

Tzvetan Todorov

Australian Journal Of International Affairs (2012)

Christian Dietrich

10.1080/10357718.2012.642712

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Citations (0)