Kai HöfigSiemens · Department of Corporate Technology (CT)
Kai Höfig
Dr.-Ing.
About
52
Publications
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274
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Introduction
Additional affiliations
April 2009 - April 2012
Publications
Publications (52)
The growing complexity of safety-relevant systems causes an increasing effort for safety assurance. The reduction of development costs and time-to-market, while guaranteeing safe operation, is therefore a major challenge. In order to enable efficient safety assessment of complex architectures, we present an approach, which combines deductive safety...
Model-based engineering promises to boost productivity and quality of complex systems development. In the context of safety-critical systems, a traditionally highly regulated and conservative domain, the use of models gained importance in the recent years. In this paper, we present a set of practical challenges in developing safety-critical systems...
The open and cooperative nature of Cyber-Physical Systems (CPS) poses new challenges in assuring dependability. The DEIS project (Dependability Engineering Innovation for automotive CPS. This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 732242, see http://www.deis-pro...
In this work, we outline a cross-domain assurance process for safety-relevant software in embedded systems. This process aims to be applied in various different application domains and in conjunction with any development methodology. With this approach we plan to reduce the growing effort for safety assessment in embedded systems by reusing safety...
Identifying drawbacks or insufficiencies in terms of safety is important also in early development stages of safety critical systems. In industry, development artefacts such as components or units, are often reused from existing artefacts to save time and costs. When development artefacts are reused, their existing safety analysis models are an imp...
Growing individualization of products up to lot-size-1 and high volatility of product mixes lead to new challenges in the manufacturing domain, including the need for frequent reconfiguration of the system and reacting to changing orders. Thus, apart from functional aspects, safety aspects of the production system as well as product quality assuran...
Cyber-Physical Systems (CPS) provide enormous potential for innovation but a precondition for this is that the issue of dependability has been addressed. This paper presents the concept of a Digital Dependability Identity (DDI) of a component or system as foundation for assuring the dependability of CPS. A DDI is an analyzable and potentially execu...
In order to enable model-based, iterative design of safety-relevant systems, an efficient incorporation of safety and system engineering is a pressing need. Our approach interconnects system design and safety analysis models efficiently using a dedicated reference model. Since all information are available in a structured way, traceability between...
The growing size and complexity of software in embedded systems poses new challenges to the safety assessment of embedded control systems. In industrial practice, the control software is mostly treated as a black box during the system's safety analysis. The appropriate representation of the failure propagation of the software is a pressing need in...
The importance of mission or safety critical software systems in many application domains of embedded systems is continuously growing, and so is the effort and complexity for reliability and safety analysis. Model driven development is currently one of the key approaches to cope with increasing development complexity, in general. Applying similar c...
Short product lifecycles and a high variety of products force industrial manufacturing processes to change frequently. Due to the manual approach of many quality analysis techniques, they can significantly slow down adaption processes of production systems or make production unprofitable. Therefore, automating them can be a key technology for keepi...
This book constitutes the proceedings of the 7th International Symposium on Model-Based Safety and Assessment, IMBSA 2020, held in Lisbon, Portugal, in September 2020. The conference was held virtually due to the COVID-19 pandemic.
The 15 revised full papers and 4 short papers presented were carefully reviewed and selected from 30 initial submissio...
Growing individualization of products up to lot-size-1 and high volatility of product mixes lead to new challenges in the manufacturing domain, including the need for frequent reconfiguration of the system and reacting to changing orders. Thus, apart from functional aspects, safety aspects of the production system as well as product quality assuran...
Presentation slides belonging to the linked conference paper
When dealing with structural safety analysis, one of the most
popular methodologies is Fault Tree Analysis (FTA). However, one major
critique is the rapid increase of the complexity, and therefore incomprehensibility,
when dealing with realistic systems. One approach to
overcome this are Component Fault Trees (CFT), presenting an extension
to stand...
Component Fault Trees (CFTs) were invented in 2003 as a compositional extension to fault trees to better reflect the technical architecture of a system in its safety analysis model. Since then, a lot of research has been contributed regarding semantic extensions, evaluation techniques, and tighter linking between system and safety models. This pape...
To encounter the challenges of faster changing markets and growing individualization of customer requests as well as to efficiently deal with internal disturbances like machine failures, an enhanced adaptability and flexibility of industrial factories is required. In this paper, challenges in the engineering of adaptable and flexible factories are...
The importance of mission or safety critical software systems in many application domains of embedded systems is continuously growing, and so is the effort and complexity for reliability and safety analysis. Model driven development is currently one of the key approaches to cope with increasing development complexity, in general. Applying similar c...
The open and cooperative nature of Cyber-Physical Systems (CPS) poses new challenges in assuring dependability. The DEIS project (Dependability Engineering Innovation for automotive CPS. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 732242, see http://www.deis-pro...
Modern embedded systems, for instance in the automotive and medical domain, have grown over the last years in terms of both size and complexity. Safety engineers are confronted with large sets of configurations to analyze during safety assessment. Due to the costliness, these assessments are typically carried out late in the development process, ma...
The growing complexity of safety-relevant systems causes an increasing effort for safety assurance. The reduction of development costs and time-to-market, while guaranteeing safe operation, is therefore a major challenge. In order to enable efficient safety assessment of complex architectures, we present an approach, which combines deductive safety...
Safety assurance is a major challenge in the design of today's complex embedded systems and future Cyber-physical systems. Changes in a system's architectural design invalidate former safety analyses and require a manual adaptation of related safety analysis models in order to restore consistency. In this work, we present an approach for automating...
Model-based engineering promises to boost productivity and quality of complex systems development. In the context of safety-critical systems, a traditionally highly regulated and conservative domain, the use of models gained importance in the recent years. In this paper, we present a set of practical challenges in developing safety-critical systems...
In order to enable model-based, iterative design of safety-relevant systems, an efficient incorporation of safety and system engineering is a pressing need. Our approach interconnects system design and safety analysis models efficiently using a dedicated reference model. Since all information are available in a structured way, traceability between...
Cyber-Physical Systems (CPS) provide enormous potential for innovation but a precondition for this is that the issue of dependability has been addressed. This paper presents the concept of a Digital Dependability Identity (DDI) of a component or system as foundation for assuring the dependability of CPS. A DDI is an analyzable and potentially execu...
Safety assurance is a major challenge in the design of today's complex embedded systems and future Cyber-physical systems. Especially changes in a system's architectural design invalidate former safety analyses and require an adaptation of related safety analysis models in order to restore consistency. In this work, we present an approach for autom...
Intensive testing is used during the development of safety-critical systems to document the conformity of software, hardware components, subsystems or the entire system to its specification. Generating test cases is a critical task itself, since complex systems cannot be tested exhaustively due to their possible infinite state space. Instead, tests...
Safety assurance is a major challenge in the design of complex embedded and Cyber-physical Systems. Especially, changes and adoptions during the design or run-time of an embedded system invalidate former safety analyses and require an adaptation of the system's safety analysis models. In this paper, we present a methodology to fill up empty safety...
Failure mode and effects analysis (FMEA), is a widely used deductive failure analysis for safety critical systems. Since modern safety critical systems tend to increased complexity, automation and tool support have a long history in research and industry. Whereas compact embedded systems can be analyzed using FMEA in a manually maintained table usi...
A popular trend to handle safety analysis of complex software intensive embedded systems is integrated model-based safety analysis. Well accepted safety engineering approaches like fault trees are shifted to the level of model-driven development by integrating safety models into functional development models. On the one hand this provides benefits...
In this work, we outline a cross-domain assurance process for safety-relevant software in embedded systems. It aims to be applied in various different application domains and in conjunction with any development methodology. With this approach we plan to reduce the growing effort for safety assessment in embedded systems by reusing safety analysis t...
(Background) Empirical Software Engineering (SE) strives to provide empirical evidence about the pros and cons of SE approaches. This kind of knowledge becomes relevant when the issue is whether to change from a currently employed approach to a new one or not. An informed decision is required and is particularly important in the development of safe...
In safety analysis for safety-critical embedded systems, methods such as FMEA and fault trees (FT) are primarily established in practice. However, the current paradigm shift towards model-based development results in various new safety analysis methods, such as Component Integrated Fault Trees (CFT). Industry demands to know the benefits of these n...
Safety is typically defined as freedom from unacceptable risk (of harm) To ensure a certain level of quality, in most industrial domains the development of safety-critical systems is governed by standards.
Embedded real-time systems are growing in complexity, which goes far beyond simplistic closed-loop functionality. Current approaches for worst-case execution time (WCET) analysis are used to verify the deadlines of such systems. These approaches calculate or measure the WCET as a single value that is expected as an upper bound for a system's execut...
The growing complexity of safety-critical embedded systems is leading to an increased complexity of safety analysis models. Often used fault tolerance mechanisms have complex failure behavior and produce overhead compared to systems without such mechanisms. The question arises whether the overhead for fault tolerance is acceptable for the increased...
Embedded real-time systems are growing in complexity, which goes far beyond simplistic closedloop functionality. Current approaches of worst-case execution time (WCET) analysis are used to verify deadlines of such systems, especially when they are safety critical. These approaches calculate or measure WCET as a single value that is expected as an u...
The number of embedded systems in our daily lives that are distributed, hidden, and ubiquitous continues to increase. Many of them are safety-critical. To provide additional or better functionalities, they are becoming more and more complex, which makes it difficult to guarantee safety. It is undisputed that safety must be considered before the sta...
Efficient safety analyses of complex software intensive embedded systems are still a challenging task. This article illustrates
how model-driven development principles can be used in safety engineering to reduce cost and effort. To this end, the article
shows how well accepted safety engineering approaches can be shifted to the level of model-drive...
The growing complexity of safety-critical systems is leading to an increased complexity of safety analysis models. Automatic transformations from the system model into the safety analysis model help to reduce time and cost for safety analyses. In this paper, we describe a pattern annotation framework for development models of safety-critical system...
We describe the direct isolation of specific antibodies on formalin-fixed, paraffin-embedded (FFPE) tissue. The technique involves subtractive selection of a large and highly diverse combinatorial human antibody phage library (HuCAL) on lymphocyte FFPE tissue sections. Tissue sections from normal human tonsil tissue were used to deplete the library...
Projects
Project (1)
CrESt is a research project with over 20 partners from industry and academia funded by the German federal ministry of education and research.
The project focuses on engineering challenges for collaborative embedded systems including (1) open and uncertain context, (2) flexible architectures, and (3) connected embedded systems. The project's objective is to define a model-based development methodology and tool support for mastering these challenges.
See https://crest.in.tum.de/ for more information.
