Interfacing to Time-Triggered Communication Systems

Time-triggered communication facilitates the construction of multi-component real-time systems whose components are in control of their temporal behavior. However, the interface of a time-triggered communication system has to be accessed with care, to avoid that the temporal independence of components gets lost. This paper shows two interfacing strategies, one for asynchronous interface access (in two variants, one being the new Rate-Bounded Non-Blocking Communication protocol) and one for time-aware, synchronized interface access, that allow components to maintain temporal independence. The paper describes and compares the interfacing strategies.Final Accepted Versio

Development of a framework for automated systematic testing of safety-critical embedded systems

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”In this paper we introduce the development of a framework for testing safety-critical embedded systems based on the concepts of model-based testing. In model-based testing the test cases are derived from a model of the system under test. In our approach the model is an automaton model that is automatically extracted from the C-source code of the system under test. Beside random test data generation the test case generation uses formal methods, in detail model checking techniques. To find appropriate test cases we use the requirements defined in the system specification. To cover further execution paths we developed an additional, to our best knowledge, novel method based on special structural coverage criteria. We present preliminary results on the model extraction using a concrete industrial case study from the automotive domain

Response functions as quantifiers of non-Markovianity

Quantum non-Markovianity is crucially related to the study of dynamical maps, which are usually derived for initially factorized system-bath states. We here demonstrate that linear response theory also provides a way to derive dynamical maps, but for initially correlated (and in general entangled) states. Importantly, these maps are always time-translational invariant and allow for a much simpler quantification of non-Markovianity compared to previous approaches. We apply our theory to the Caldeira-Leggett model, for which our quantifier is valid beyond linear response and can be expressed analytically. We find that a classical Brownian particle coupled to an Ohmic bath can already exhibit non-Markovian behaviour, a phenomenon related to the initial state preparation procedure. Furthermore, for a peaked spectral density we demonstrate that there is no monotonic relation between our quantifier and the system-bath coupling strength, the sharpness of the peak or the resonance frequency in the bath.Comment: Updated version with additional information. 5 + 5 pages incl. 2 figures. Comments are welcom

Comparison of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in the serum of hypothyroxinemic and euthyroid dogs.

ObjectiveTo determine the profile of 14 polybrominated diphenyl ethers (PBDEs) and 23 polychlorinated biphenyls (PCBs) in serum of domestic canines and whether this was predictive of thyroid hormone status.SamplesSerum samples were collected from 51 client-owned dogs visiting the University of California Davis William R. Pritchard Veterinary Medical Teaching Hospital during 2012 to 2016 for routine appointments. Fifteen dogs were diagnosed with hypothyroxinemia while 36 were euthyroid.ProceduresConcentrations of PBDEs and PCBs in canine serum samples were measured by gas chromatography mass spectrometry. Logistic regression analysis was used to determine the association between the presence/absence of canine hypothyroxinemia and the serum concentration of individual PBDE or PCB congeners.ResultsThe median concentrations of total PBDE and PCB congeners in the hypothyroxinemic group were 660 and 1,371 ng/g lipid, respectively, which were higher than concentrations detected in the control group. However, logistic regression analysis determined that current concentrations of PBDEs and PCBs in canines were not significantly associated with hypothyroxinemia. BDE 183 was the only congener showing near significance (p = 0.068).ConclusionsPBDE and PCB congeners were detected in all canine samples confirming ongoing exposure to these pollutants. Because household dogs share the human environment, they may serve as biosentinels of human exposure to these contaminants

Fully automatic worst-case execution time analysis for MATLAB/Simulink models

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”In today's technical world (e.g., in the automotive industry), more and more purely mechanical components get replaced by electro-mechanical ones. Thus the size and complexity of embedded systems steadily increases. To cope with this development, comfortable software engineering tools are being developed that allow a more functionality-oriented development of applications. The paper demonstrates how worst-case execution time (WCET) analysis is integrated into such a high-level application design and simulation tool MATLAB/Simulink-thus providing a higher-level interface to WCET analysis. The MATLAB/Simulink extensions compute and display worst-case timing data for all blocks of a MATLAB/Simulink simulation, which gives the developer of an application valuable feedback about the correct timing of the application being developed. The solution facilitates a fully-automated WCET analysis, i.e., in contrast to existing approaches the programmer does not have to provide path information

A Code Policy Guaranteeing Fully Automated Path Analysis

Calculating the worst-case execution time (WCET) of real-time tasks is still a tedious job. Programmers are required to provide additional information on the program flow, analyzing subtle, context dependent loop bounds manually. In this paper, we propose to restrict written and generated code to the class of programs with input-data independent loop counters. The proposed policy builds on the ideas of single-path code, but only requires partial input-data independence. It is always possible to find precise loop bounds for these programs, using an efficient variant of abstract execution. The systematic construction of tasks following the policy is facilitated by embedding knowledge on input-data dependence in function interfaces and types. Several algorithms and benchmarks are analyzed to show that this restriction is indeed a good candidate for removing the need for manual annotations

Timing analysis of optimised code

Timing analysis is a crucial test for dependable hard real-time systems (DHRTS). The calculation of the worst-case execution time (WCET) is mandatory. As modern compilers are capable to produce small and efficient code, software development for DHRTS today is mostly done in high-level languages instead of assembly code. Execution path information available at source code (flow facts) therefore have to be transformed correctly in accordance with code optimisations by the compiler to allow safe and precise WCET analysis. In this paper we present a framework based on abstract interpretation to perform this mandatory transformation of flow facts. Conventional WCET analysis approaches use this information to analyse the object code

Classification of Code Annotations and Discussion of Compiler-Support for Worst-Case Execution Time Analysis

Tools for worst-case execution time (WCET) analysis request several code annotations from the user. However, most of them could be avoided or being annotated more comfortably if the compilers would support WCET analysis. This paper provides a clear categorization of code annotations for WCET analysis and discusses the positive impact on code annotations a compiler-support on WCET analysis would have

Stories of extractivism and transformation

Diese Studie befasst sich mit den durch den Bergbau verursachten Umwelt- Sozial- und Territorialkonflikten in der Region Tarapacá, deren Probleme nicht nur mit den Umweltauswirkungen, sondern mit der allgemeinen Behandlung der Natur zum Zwecke des Profits und des Exports verbunden sind. Die Monographie konzentriert sich auf die Konfrontation zwischen dem Staat, den indigenen Gemeinschaften und den Bergbauunternehmen und beschreibt nuanciert die vielen Beziehungen und Verflechtungen zwischen ihnen. Im Mittelpunkt dieser Arbeit stehen die verschiedenen politischen, wirtschaftlichen, institutionellen und kulturellen Elemente im Zusammenhang mit der Entwicklung von Bergbau und ihre Folgen und Interdependenzen die in den einzelnen Kapiteln beschrieben und dargestellt werden. Im Rahmen nationaler Umweltvorschriften, die die Entwicklung des Bergbaus und anderer Tätigkeiten mit großen Auswirkungen auf die Umwelt zu regulieren versuchen, generiert der heutige ressourcenabbau bestimmte Vereinbarungen mit den lokalen Gemeinschaften die in der Nähe der Bergbaugebiete leben. Das Fehlen von Vereinbarungen kann zu Konflikten und Widerstand seitens der Gemeinschaften führen. Dadurch könnten bestimmte Bergbauprojekte mit hohen Investitionskosten gestoppt oder verzögert werden. Auf diese Weise werden Institutionen, unternehmerisches Engagement, Partizipation und Widerstand in komplexen Beziehungen miteinander verwoben. Die Arbeit integriert auch einen historischen Rahmen in Anbetracht des früheren Salpeterabbaus in der Region und der Entwicklung der Chilenischen Ressourcenpolitik des 20. Jh. mit starken Einfluss auf die nationale Vorstellung vom Bergbau als grundlegende Wirtschaftstätigkeit für die nationale Entwicklung. Sowohl werden auch die Merkmale des chilenischen Neoliberalismus und die Rolle des Bergbaus anhand einer Extraktivismus Kritik behandelt.This study addresses the environmental, social, and territorial conflicts caused by mining in the Tarapacá region, whose problems are linked to environmental impacts and the general treatment of nature for profit and export. The study focuses on the confrontation between the state, indigenous communities, and mining companies and describes the many relationships and interconnections between them in nuanced terms. This work focuses on the various political, economic, institutional, and cultural elements associated with mining development and their consequences and interdependencies, which are described and illustrated in each chapter. In the context of national environmental regulations that seek to regulate the development of mining and other activities with significant environmental impacts, contemporary resource extraction generates certain agreements with local communities living near mining areas. The lack of agreements can lead to conflict and resistance from communities, and this could stop or delay specific mining projects with high investment costs. This way, institutions, corporate engagement, participation, and resistance become interwoven in complex relationships. The work also integrates a historical framework considering the former saltpeter mining in the region and the development of Chilean resource policies of the 20th century, with a strong influence on the national conception of mining as a fundamental economic activity for national development, discussing at large the characteristics of Chilean neoliberalism and the role of mining