Peleska, Jan
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Peleska, Jan
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Peleska, Jan
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Item-typ:Veröffentlichung, A Framework for Model-based Testing of Integrated Modular Avionics(2014-12-10); ; ; In modern aircraft, electronics and control systems are designed based on the Integrated Modular Avionics (IMA) system architecture. While this has numerous advantages (reduction of weight, reduced power and fuel consumption, reduction of development cost and certification effort), the IMA platform also adds an additional layer of complexity. Due to the safety-critical nature of many avionics functions careful and accurate verification and testing are imperative. This thesis describes results achieved from research on model-based testing of IMA systems, in part obtained during the European research project SCARLETT. It presents a complete framework which enables IMA domain experts to design and run model-based tests on bare module, configured module, and application level in a standardised test environment. The first part of this thesis provides background information on the relevant topics: the IMA concept, domain-specific languages, model-based testing, and the TTCN-3 standard. The second part introduces the IMA Test Modelling Language (ITML) framework and its components. It describes a tailored TTCN-3 test environment with appropriate adapters and codecs. Based on MetaEdit and its meta-metamodel GOPPRR, it defines the three variants of the domain-specific language ITML, each with its abstract and concrete syntax as well as static and dynamic semantics. The process of test procedure generation from ITML models is explained in detail. Furthermore, the design and implementation of a universal Test Agent is shown. A dedicated communication protocol for controlling the agent is defined as well. The third part provides an evaluation of the framework. It shows usage scenarios in the SCARLETT project, gives a comparison to related tools and approaches, and explains the advantages of using the ITML framework for an IMA domain expert. The final part presents several example ITML models. It also provides reference material like XML schemata, framework source code, and model validators.Dissertation829 460 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Open Source Software for Train Control Applications and its Architectural Implications(2013-02-21); ; ; ; This document describes the research results that were obtained from the development of safety-critical software under the principles of open source. Different model-based designs and architectures within the railway control system application domain, including re-usable formalisms for verification & validation, were investigated. The reduction of possible security threats caused by platform or supplier specific adaptations of modelled open-core software was analysed, and a possible solution by the usage of hardware virtualisation, instead of traditional memory management, was elaborated. At core of this work, the development of a graphical domain-specific language for modelling parts of the European Train Control System (ETCS) is presented, which is based on specialised data, control flow formalisms, and language elements derived from the specification document. For a more precise and therefore more appropriate syntax definition for safety-critical systems, the already existing GOPRR meta meta model was extended to the newly developed GOPPRR meta meta model. GOPPRR includes methods for defining constraints by the object constraint language, which supports the definition of static semantics to ensure correct model instances. Parts of the ETCS specification related to the train on-board unit were modelled in a new meta model. To transform the developed model of the ETCS specification into an executable application, a domain framework, according to the new meta model and the corresponding code generator, were designed and implemented, which have implicitly an integrated support for the verification & validation process. To proof the correctness of the modelled specification, the resulting application was executed in a simulative environment to obtain simulation traces. The correspondence of traces to the expected data from the specification document supported the used methods and strategies in this dissertation as proof of concept.Dissertation935 894 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Hard Real-Time Linux for Off-The-Shelf Multicore Architectures(2015-11-10); ; ; This document describes the research results that were obtained from the development of a real-time extension for the Linux operating system. The paper describes a full extension of the kernel, which enables hard real-time performance on a 64-bit x86 architecture. In the first part of this study, real-time systems are categorized and concepts of real-time operating systems are introduced to the reader. In addition, numerous well-known real-time operating systems are considered. QNX Neutrino, RT_PREEMPT Linux Patch and HLRT Linux Patch are analyzed in detail. The core concepts of these systems are shown and discussed. Furthermore, a test suite is developed, which is used to obtain expressive benchmarks from the systems that were analyzed before. The systems are evaluated on the basis of these benchmarks and compared to the real-time extension which is developed in this work. A requirements catalogue is defined based on the analysis of the stated operating systems. The design of a real-time extension is developed based on the specification catalogue and the identified core concepts. Furthermore, the concrete implementation of the developed real-time extension is presented in detail. Finally, the benchmarks of all analyzed systems, including the developed real-time extension, are compared to each other and evaluated.Dissertation548 433 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, System Testing in the Avionics Domain(2007-12-18); ; ; When developing a new aircraft, the airframer encounters various (partly contradictory) demands and requirements. To deal with them, current avionics systems are based on the framework of integrated modular electronics which allows to use COTS products for less critical functions and uses integrated modular avionics (IMA) technology for safety-critical avionics functions. Since this evolution affects the entire development, new processes and means for the development and the verification and validation of avionics systems are required.This thesis addresses this evolution from two angles: 1) A systems engineering part introduces the general processes and approaches to be considered when developing and testing avionics systems and describes how the technology and the development processes have evolved, particularly with respect to system testing in avionics. 2) Two case studies detail the described testing activities during system integration for two newly identified testing areas.Dissertation454 1840 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Complete Model-Based Testing Applied to the Railway Domain(2018-01-10); ; ; Testing is the most important verification technique to assert the correctness of an embedded system. Model-based testing (MBT) is a popular approach that generates test cases from models automatically. For the verification of safety-critical systems, complete MBT strategies are most promising. Complete testing strategies can guarantee that all errors of a certain kind are revealed by the generated test suite, given that the system-under-test fulfils several hypotheses. This work presents a complete testing strategy which is based on equivalence class abstraction. Using this approach, reactive systems, with a potentially infinite input domain but finitely many internal states, can be abstracted to finite-state machines. This allows for the generation of finite test suites providing completeness. However, for a system-under-test, it is hard to prove the validity of the hypotheses which justify the completeness of the applied testing strategy. Therefore, we experimentally evaluate the fault-detection capabilities of our equivalence class testing strategy in this work. We use a novel mutation-analysis strategy which introduces artificial errors to a SystemC model to mimic typical HW/SW integration errors. We provide experimental results that show the adequacy of our approach considering case studies from the railway domain (i.e., a speed-monitoring function and an interlocking-system controller) and from the automotive domain (i.e., an airbag controller). Furthermore, we present extensions to the equivalence class testing strategy. We show that a combination with randomisation and boundary-value selection is able to significantly increase the probability to detect HW/SW integration errors.Dissertation421 249 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, The Convex Hull Problem in Practice : Improving the Running Time of the Double Description Method(2015-01-28); ; ; The double description method is a simple but widely used algorithm for computation of extreme points in polyhedral sets. One key aspect of its implementation is the question of how to efficiently test extreme points for adjacency. In this dissertation, two significant contributions related to adjacency testing are presented. First, the currently used data structures are revisited and various optimizations are proposed. Empirical evidence is provided to demonstrate their competitiveness. Second, a new adjacency test is introduced. It is a refinement of the well known algebraic test featuring a technique for avoiding redundant computations. Its correctness is formally proven. Its superiority in multiple degenerate scenarios is demonstrated through experimental results. Parallel computation is one further aspect of the double description method covered in this work. A recently introduced divide-and-conquer technique is revisited and considerable practical limitations are demonstrated.Dissertation683 977 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, High Level Transition Systems of CSP Specifications and their Application in Automated Testing(2004-02-02); ; ; ; State of the art quality assurance for safety critical software systems requires formal methods for verification and testing. The context of this thesis is the field of specification based testing of embedded reactive real-time systems. The authors present an approach to reduce the problem of state explosions using a representation of the transition system of a CSP specification, that does not require the calculation of the complete state space.The new representation consists of two parts: High-Level transition graphs (HLTG) to model sequential processes containing only low-level CSP operators and synchronisation terms that represent the high-level communication structure of sequential components expressed using high-level transition graphs. HLTG are an extension of conventional transition systems, which contain events, conditions and assignments of CSP specifications at the transitions, containing parameters and parametrised expressions. The value of a parameter is bound through assignments at transitions, which are created for the CSP operators prefixing and process references. A node in a HLTG can represent multiple states of the complete state space. The interpretation of a HLTG requires the evaluation of the conditions, events and assignments of a transition to perform a state change.Real-time testing requires an upper bound of time required for the calculation of the initial actions and refusals of a location. This can be achieved by using normalised transition systems. Different stages of the normalisation of HLTG and synchronisation terms have been developed. To enable real-time testing with unnormalised graphs, an on-the-fly normalisation is introduced. For those cases, where test evaluation needs not to be performed in real-time, a new test algorithm for a delayed test evaluation is suggested, which can be used for testing purposes based on any type of transition systems, even unnormalised systems.Dissertation489 245 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Architekturkonzept und Designaspekteeiner signaltechnisch nichtsicheren Kommunikationsplattformfür sicherheitsrelevante Bahnanwendungen(2004-01-28); ; ; In this dissertation a design for a communication platform for distributed railway applications is presented. A strict separation of fail-safe and non-fail-safe functionalities and a decoupling to the greatest possible extent of communication functions from the railway applications permit the use of standardised communication infrastructures and technologies from the field of distributed communications. Through the service integration of the preceding gateway functionality the utilisation of the limited transmission capacity of the existing communication infrastructure can be considerably increased.The stringent demands made on the reliability of the overall system are satisfied by the use of special failure-tolerant link protocols and the creation of redundant gateway clusters. The advantage of using the special link protocols lies in the reduced complexity on the fail-safe signalling&safety side. For the implementation of the switching and protocol functionalities of the preceding gateway entity, a framework running in user space with special resources was created within the communication platform.For the validation of the communication platform the following hardware-in-the-loop strategy was applied:Communication scenarios are stimulated by a test environment and tested automatically. Besides the verification of the correctness of the exchanged data and consistency of the protocol primitives received at the user interface of the unit under test, the transfers can also be observed at the interfaces between the protocol layers. In order to demonstrate conformity, a concept was developed based on a layer-wise analysis of the protocol data stream of the communication stack to be tested.Dissertation252 115 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Testing End-To-End Chains using Domain Specific Languages(2015-11-25); ; ; Testing systems is a time consuming (and hence expensive) activity. Nevertheless, it is a very important and necessary step before using systems, especially safety critical systems. Therefore, many different test procedures are used: Unit Tests, Black-Box Tests, Software Integration Tests (SWI), Hardware-Software Integration Tests (HSI), Hardware-In-The-Loop Tests, just to name a few. Especially in the avionics domain, a variety of systems and applications communicate which each other. Furthermore, they depend and rely on the received information. However, some faults are only detected when all systems are connected and in operational mode. A new testing approach is to create model based End-To-End Chain scenarios with original and simulated equipment in any combination. The first aim is to automatically derive test data and test cases from the model, which is defined by a Domain Specific Language (DSL). Test data generators can be attached to quickly create a variety of stimuli for the systems under test. Furthermore, the system under test can be stimulated by either original equipment which is connected to the test bench or the test bench can simulate equipment and create inputs for the tested systems. Any mixture of simulated and original equipment is possible and can be changed on the fly. In the end, the results from the system under test are collected. These results can then be displayed back in the model. This method was used and improved in the project E-Enabled Cabin (E-Cab) in which the author was involved. Passengers traveling by plane are in the focus of this project. Complete services and service chains ranging from booking at home with a computer, being en route using mobile devices to leaving the destination airport are created and used by many systems communicating with each other. A special focus is set on a guidance scenario at an airport. The user of the system signs in to a guidance and notification system which will inform him via his own digital equipment (mobile device/smart phone). The system notifies the user about his in-time status. Either he is in-time for his flight, or he needs to hurry up and proceed to the next area or he will be too late and cannot catch his flight. The DSL itself is designed according to the comprehension of information processes. The ability of the human brain to process visual information in parallel in contrast to sequential processing of textual information is described and applied in the design of the DSL and the concepts of the project. The development of the DSL and the workflow is developed with the real world in mind. This means that the work fits in established workflows and enhances the current situation. As this project took place in the aircraft industry, the appropriate development standards, like DO178B and ABD100/200 (Airbus Directives ABD100/ABD200), build the foundation. The generation of clean code is established by applying generator guidelines (through coding standards) in order to create maintainable tests and test data.Dissertation477 234 - Some of the metrics are blocked by yourconsent settings
Item-typ:Veröffentlichung, Model-Based Scenario Testing and Model Checking with Applications in the Railway Domain(2015-02-05); ; ; This thesis introduces Timed Moore Automata, a specification formalism, which extends the classical Moore Automata by adding the concept of abstract timers without concrete delay time values, which can be started and reset, and which can change their state from running to elapsed. The formalism is used in real-world railway domain applications, and algorithms for the automated test data generation and explicit model checking of Timed Moore Automata models are presented. In addition, this thesis deals with test data generation for larger scale test models using standardized modeling formalisms. An existing framework for the automated test data generation is presented, and its underlying work-flow is extended and modified in order to allow user interaction and guidance within the generation process. As opposed to specifying generation constraints for entire test scenarios, the modified work flow then allows for an iterative approach to elaborating and formalizing test generation goals.Dissertation794 285