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Felbinger H.,Virtual Vehicle | Wotawa F.,Graz University of Technology | Nica M.,AVL List GmbH
Proceedings - 11th International Workshop on Automation of Software Test, AST 2016 | Year: 2016

In this paper we investigate a method for test suite evaluation that is based on an inferred model from the test suite. The idea is to use the similarity between the inferred model and the system under test as a measure of test suite adequacy, which is the ability of a test suite to expose errors in the system under test. We define similarity using the root mean squared error computed from the differences of the system under test output and the model output for certain inputs not used for model inference. In the paper we introduce the approach and provide results of an experimental evaluation where we compare the similarity with the mutation score. We used the Pearson Correlation coefficient to calculate whether a linear correlation between mutation score and root mean squared error exists. As a result we obtain that in certain cases the computed similarity strongly correlates with the mutation score. © 2016 ACM.

Theissl H.,AVL List GmbH | Danninger A.,Virtual Vehicle | Sacher T.,AVL List GmbH | Ofner H.,AVL List GmbH | Schalk E.,Virtual Vehicle
SAE International Journal of Engines | Year: 2013

This paper describes a method for optimization of engine settings in view of best total cost of operation fluids. Under specific legal NOX tailpipe emissions requirements the engine out NOX can be matched to the current achievable SCR NOX conversion efficiency. In view of a heavy duty long haul truck application various specific engine operation modes are defined. A heavy duty diesel engine was calibrated for all operation modes in an engine test cell. The characteristics of engine operation are demonstrated in different transient test cycles. Optimum engine operation mode (EOM) selection strategies between individual engine operation modes are discussed in view of legal test cycles and real world driving cycles which have been derived from on-road tests. Copyright © 2013 SAE International.

Kitanoski F.,Virtual Vehicle | Hofer A.,University of Graz
IFAC Proceedings Volumes (IFAC-PapersOnline) | Year: 2010

Hybrid electric vehicles are regarded as a possible solution for the reduction of pollutant emissions and for improving the fuel economy. Besides the conventional cooling circuit for the engine, hybrid vehicles need cooling for the electrical drives and for the energy storage systems as well. The development of appropriate cooling systems has the consequence that the number of auxiliary components involved, the weight and above all the energy consumption is increased. Therefore in order to minimize the energy consumption an optimal strategy for the operation of the cooling aggregates is required. In this paper an approach for finding the optimal control strategy of the electric auxiliaries over an apriori defined driving cycle is introduced. An energy minimization problem with constraints given by the maximum allowed temperature of the components is stated. This problem is based on a nonlinear mathematical model of the cooling system. It is shown how the nonlinear continuous time model can be equivalently replaced by a suitable linear discrete time model where some of the variables are confined to take integer values. This allows us to cast the optimization problem as a mixed integer linear program. The proposed approach is demonstrated by an example. For this purpose a cooling system is considered where an electrically driven water pump and an electric cooling fan are involved. As a result the optimal interaction of the water pump and the fan is computed such that the energy consumption of these components is minimized subject to given temperature constraints. © 2010 IFAC.

Schwarzl C.,Virtual Vehicle | Peischl B.,University of Graz
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

UML state chart models describing the behavior of a system can be used as a formal specification thereof. The existence of advanced modeling tools allows for model simulation and enables the execution of manually created tests on the models. In this work the usage of static and dynamic model analysis techniques is proposed to reveal errors in these models. The static analysis focuses on the syntax, communication structure and non-determinism. The dynamic analysis is based on a random test approach and can reveal bugs like deadlocks and inter-model loops. Further the data generated during the dynamic analysis allows for additional correctness checks such as e.g. the number or lengths of paths. The presented approach is implemented in a prototype and revealed several bugs in an industrial case study not found during simulation and manual model testing. © 2010 Springer-Verlag.

Schwarzl C.,Virtual Vehicle | Peischl B.,University of Graz
Proceedings - International Conference on Software Engineering | Year: 2010

The further automation of the test development process beyond the automatic execution of tests is an increasing challenge, because the development of new functionalities has a higher pace than the test development. The use of model based techniques combined with test generation methods enable a fast test definition while the test oracle is calculated automatically. The presented approach was implemented in a research prototype, which was used to generate test cases out of an UML state chart model describing the behavior of the system under test. The resulting test sequences were executed on a hardware in the loop (HiL) and showed its applicability in an industrial setting. Copyright 2010 ACM.

Polzlbauer F.,Virtual Vehicle | Bate I.,University of York | Brenner E.,University of Graz
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

In modern embedded systems, e.g. avionics and automotive, it is not unusual for there to be between 40 and 100 processors with a great deal of the software having hard real-time requirements and constraints over how, when and where they execute. The requirements and constraints are essential to the overall systems dependability and safety (e.g. to ensure replicas execute on different hardware). This leads to a complex design space exploration (DSE) problem which cannot be practically solved manually especially if the schedule is to be maintained. In this paper it is shown that dealing with the constraints using a conventional state of the art "System Configuration Algorithm" is less efficient, less effective and does not scale well. This issue can be improved by performing constraint pre-processing as well as constraint encoding. It is shown that our approach can handle typical industrial requirements that come from the automotive industry's AUTOSAR standard in an efficient way. © 2012 Springer-Verlag.

Polzlbauer F.,Virtual Vehicle | Bate I.,University of York | Brenner E.,University of Graz
IEEE Embedded Systems Letters | Year: 2012

During system synthesis (i.e., task allocation) the transmission of messages between tasks is usually addressed in a simplistic way. If a message is exchanged via an external bus, it is assumed each message is packed in an individual frame. This assumption leads to an overestimation of bus bandwidth demand and frame response time. For some systems (i.e., automotive), this pessimism is not acceptable and therefore frame packing is often performed where multiple messages are packed into a single frame. In this paper, an improved frame packing approach is provided. © 2009-2012 IEEE.

Kitting D.,Virtual Vehicle | Ofenheimer A.,Virtual Vehicle | Pauli H.,Voestalpine AG | Till E.T.,Voestalpine AG
International Journal of Material Forming | Year: 2010

In sheet forming, stretch-bending deformation, (i.e. combined deformation of simultaneous stretching and bending when sheet material is stretched over a defined tool radius), is known to enhance material formability. In order to use this forming potential of sheet material, current research put its emphasis on the experimental characterization of the formability of sheet material, subjected to stretch-bending deformation and on a more reliable formability prediction in complex shaped parts. Nevertheless, significant limitations exist in the current available experimental setups for the characterization of the stretch-bending formability of sheet material. Furthermore, the predictive quality of existing formability prediction models is not sufficient to meet current industrial requirements. In this work results of an experimental characterization of influences on stretch-bending formability using existing and newly developed stretch-bending test setups are presented and a phenomenological concept that uses the experimental results to predict formability in Finite-Element simulations of complex shaped parts involving stretch-bending deformation is proposed. © 2010 Springer-Verlag France.

Stocker A.,Virtual Vehicle | Muller J.,Siemens AG
Journal of Systems and Information Technology | Year: 2016

Purpose: To measure the success of corporate social software (CSS), interviews, surveys, content and usage data analysis have been commonly used in practice. While interviews and surveys are only capable of making perceived use and benefits transparent, usage data analysis reveals many objective facts but does not allow insights into potential user-benefits. Hence, the purpose of this paper is to link both perspectives to advance CSS success measuring. Design/methodology/approach: The research case is References+, a Corporate Social Software developed at Siemens to facilitate worldwide sharing of knowledge, experiences, and best practices since 2005. References+ currently has around 15,000 registered members located in more than 80 countries. This paper evaluates results from a user survey with nearly 1,500 responding employees and links all survey results to the corresponding participant’s data on platform use to generate additional insights. Findings: The paper generates findings on how CSS is used in practice and how it is perceived by employees of a large-scale enterprise. Furthermore, it explores how a combination of subjective and objective evaluation methods can be applied to advance the state-of-the-art in measuring use and benefits. By linking CSS usage data to corresponding survey data, the paper provides results on what type of use of CSS may create what type of benefit. Practical implications: This study encourages practitioners to take advantage of a variety of instruments for measuring the benefits of CSS. It generates numerous arguments for practitioners on how to make the benefit of CSS more transparent to financial-oriented decision-makers to successfully defend knowledge management projects against shrinking IT budgets. Originality/value: This paper is one of the first attempts to explore the relationship between “perceived use” and “perceived benefits” measured by surveys and “factual use” measured by CSS usage statistics for knowledge management research. The findings of this paper may empower the role of user surveys in generating additional insights on use and benefits. © 2016, © Emerald Group Publishing Limited.

Rudigier M.,Virtual Vehicle | Horn M.,Klagenfurt University
Advances in Intelligent and Soft Computing | Year: 2010

Numerical simulation is a key technology for vehicle development. In vehicle dynamics simulations, the resulting dynamics heavily depend on the interaction of the vehicle, environment and human driver. Suitable mathematical models of human drivers for automotive applications are required in order to gain significant simulation results. The driver can be regarded as a controller for the system consisting of the vehicle and environment (road and traffic). In most vehicle dynamics simulations, the driver is modeled as a controller in an engineering sense. However, characteristics that describe the "human" behavior of a driver should be taken into account as well. In the first part of this article, a short over-view of methods of modeling human drivers is given. Subsequently a driver model for vehicle dynamics simulation is presented. A set of basic and advanced use cases define the requirements for this driver model within a professional vehicle dynamics package (multi-body simulation). These use cases extend from "straight line acceleration" to complex driving maneuvers, such as the "3-point-turn", i.e. changing driving direction on a road that is narrower than the turning radius of the vehicle. The driver model is discussed based on exemplary simulation results. Finally a concept of how to adapt this model to real human behavior is presented. © 2010 Springer-Verlag Berlin Heidelberg.

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