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István Majzik - IEEE Xplore Author Profile

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Fault Tree Analysis is widely used in the reliability evaluation of critical systems, such as railway and automotive systems, power grids, and nuclear power plants. While there are efficient algorithms for calculating the probability of failure in static fault trees, Mean Time to First Failure (MTFF) evaluation remains challenging due to state space explosion. Recently, structural and symmetry red...Show More
Since safety-critical autonomous vehicles need to interact with an immensely complex and continuously changing environment, their assurance is a major challenge. While systems engineering practice necessitates assurance on multiple levels, existing research focuses dominantly on component-level assurance while neglecting complex system-level traffic scenarios. In this paper, we aim to address the ...Show More
Model-driven engineering methodologies are often used for the design and integration of the software and hardware components in automated production systems. Architecture models in general purpose or domain specific modeling languages allow the modular and systematic construction of formal analysis models for the evaluation of dependability and performability. The on-line reconfiguration and fault...Show More
The Gamma Statechart Composition Framework is an integrated tool to support the design, verification and validation as well as code generation for component-based reactive systems. The behavior of each component is captured by a statechart, while assembling the system from components is driven by a domain-specific composition language. Gamma automatically synthesizes executable Java code extending...Show More
In this paper, we present Theta, a configurable model checking framework. The goal of the framework is to support the design, execution and evaluation of abstraction refinement-based reachability analysis algorithms for models of different formalisms. It enables the definition of input formalisms, abstract domains, model interpreters, and strategies for abstraction and refinement. Currently it con...Show More
The complexity and quality needs of PLC-based control system software have largely increased. Formal specification methods can help to cope with these needs. Besides formal verification, another benefit of a formal specification language is the possibility to provide automatic generation of the final source code. This paper overviews PLCspecif, our formal specification language for PLC programs an...Show More
Verification of industrial control systems' software is an important task, as the cost of failure in these systems is typically high. Formal verification methods can complement the currently used testing techniques, especially if requirements are formally specified. Behavioural specifications can be used to perform conformance checking against the implementation. However, the typical conformance r...Show More
Stochastic aspects of complex systems require more and more involved analysis approaches. Answering reachability and related analysis questions can often be reduced to steady-state, transient, reward or sensitivity value analysis of stochastic models. In this paper we introduce a configurable stochastic analysis framework which supports the user to combine explicit, symbolic and numerical algorith...Show More
Dealing with large, critical mobile systems and infrastructures where ongoing changes and resilience are paramount leads to very complex and difficult challenges for system evaluation. These challenges call for approaches that are able to integrate several evaluation methods for the quantitative assessment of QoS indicators which have been applied so far only to a limited extent. In this paper, we...Show More
Model based dependability analysis can be used to evaluate the effects of architectural choices on system level availability and reliability. In component based systems the dependability model is built typically from sub-models that are assigned to components or subsystems and represent the local fault occurrences and error propagation. We describe the design and application of a tool that is able...Show More
Cost pressure, short time to market, and increased complexity are responsible for an evident increase of the failure rate of computing systems, while the cost of failures is growing rapidly, as a result of an unprecedented degree of dependence of our society on computing systems. The combination of these factors has created a dependability and security gap that is often perceived by users as a lac...Show More
Dependability is a fundamental property of computer systems operating in critical environment. The measurement of dependability (and thus the assessment of the solutions applied to improve dependability) typically relies on controlled fault injection experiments that are able to reveal the behavior of the system in case of faults (to test error handling and fault tolerance) or extreme input condit...Show More
This workshop summary gives a brief overview of the workshop on ldquoResilience Assessment and Dependability Benchmarkingrdquo held in conjunction with the 38th IEEE/IFIP International Conference on Dependable Systems and Networks (DSN 2008). The workshop aims at the presentation and exchange of ideas from the world wide research community and fostering discussions in order to give answers to the ...Show More
In railway train-borne equipment, the driver machine interface (DMI) acts like a bridge between the train driver and the onboard automatic train control system (European Vital Computer, EVC). While the DMI is required to operate in a critical context, current DMIs have no safety requirements. This implies that the EVC may automatically stop the train whenever the DMI is suspected to misbehave, lea...Show More
Testing is an essential, but time and resource consuming activity in the software development process. In the case of model-based development, among other subtasks test construction and test execution can be partially automated. Our paper describes the implementation of a test generator framework that uses an external model checker to construct test sequences. The possible configurations of the mo...Show More
Checking various temporal requirements is a key dependability concern in safety-critical systems. As model-checking approaches do not scale well to systems of high complexity the runtime verification of temporal requirements has received a growing attention recently. This paper presents a code-generation based method for runtime evaluation of linear temporal logic formulae over program execution t...Show More
Aspect-oriented modeling is proposed to design the architecture of fault tolerant systems. Notations are introduced that support the separate and modularized design of functional and dependability aspects in UML class diagrams. This notation designates sensitive parts of the architecture and selected architecture patterns that implement common redundancy techniques. A model weaver is presented tha...Show More
This work presents the analysis of an experiment series aiming at the discovery of the impact of two inherently different statechart implementation methods on the behavior of the resulting executables in the presence of faults. The discussion identifies the key features of implementation techniques influencing the effectiveness of standard fault detection mechanisms (memory protection, assertions ...Show More
This paper presents how the platform-specific development environment of time-triggered (TT) systems can be integrated with a visual design toolkit based on UML. The built-in facilities of UML and the modeling extensions introduced by us enable the unification of the advantages provided by both the embedded development environment and the UML tools. UML offers visual design, automatic code and doc...Show More
The VIATRA (visual automated model transformations) framework is the core of a transformation-based verification and validation environment for improving the quality of systems designed using the Unified Modeling Language by automatically checking consistency, completeness, and dependability requirements. In the current paper, we present an overview of (i) the major design goals and decisions, (ii...Show More
The paper presents techniques that enable the modeling and analysis of redundancy schemes in distributed object-oriented systems. The replication manager, as a core part of the redundancy scheme, is modeled by using UML statecharts. The flexibility of the statechart-based modeling, which includes event processing and state hierarchy, enables an easy and efficient modeling of replication strategies...Show More
Even though a thorough system specification improves the quality of the design, it is not sufficient to guarantee that a system will satisfy its reliability targets. Within this paper, we present an application example of one of the activities performed in the European ESPRIT project HIDE, aiming at the creation of an integrated environment where design toolsets based on UML are augmented with mod...Show More
The paper deals with the automatic dependability analysis of systems designed using UML. An automatic transformation is defined for the generation of models to capture systems dependability attributes, like reliability. The transformation concentrates on structural UML views, available early in the design, to operate at different levels of refinement, and tries to capture only the information rele...Show More
The need of efficient implementation, safety and performance requires early validation in the design of computer control systems. The detailed timing and reachability analysis in the development process is particularly important if we design equipments or algorithms of high performance and availability. In this paper we present a case study related to the early validation of control systems modele...Show More
Signature based error detection techniques (e.g. the application of watchdog processors) can be easily extended to support software debugging. The run-time sequence of signatures is stored in an extension of the traditional checker. As the signatures identify the states of the program, a trace of the statements executed by the checked processor is available. The signature buffer can be efficiently...Show More