Increasing System Test Coverage in Production Automation Systems

An approach is introduced, which supports a testing technician in the identification of possibly untested behavior of control software of fully integrated automated production systems (aPS). Based on an approach for guided semi-automatic system testing, execution traces are recorded during testing, allowing a subsequent coverage assessment. As the behavior of an aPS is highly dependent on the software, omitted system behavior can be identified and assessed for criticality. Through close cooperation with industry, this approach represents the first coverage assessment approach for system testing in production automation to be applied on real industrial objects and evaluated by industrial experts

Industrially Applicable System Regression Test Prioritization in Production Automation

When changes are performed on an automated production system (aPS), new faults can be accidentally introduced in the system, which are called regressions. A common method for finding these faults is regression testing. In most cases, this regression testing process is performed under high time pressure and on-site in a very uncomfortable environment. Until now, there is no automated support for finding and prioritizing system test cases regarding the fully integrated aPS that are suitable for finding regressions. Thus, the testing technician has to rely on personal intuition and experience, possibly choosing an inappropriate order of test cases, finding regressions at a very late stage of the test run. Using a suitable prioritization, this iterative process of finding and fixing regressions can be streamlined and a lot of time can be saved by executing test cases likely to identify new regressions earlier. Thus, an approach is presented in this paper that uses previously acquired runtime data from past test executions and performs a change identification and impact analysis to prioritize test cases that have a high probability to unveil regressions caused by side effects of a system change. The approach was developed in cooperation with reputable industrial partners active in the field of aPS engineering, ensuring a development in line with industrial requirements. An industrial case study and an expert evaluation were performed, showing promising results.Comment: 13 pages, https://ieeexplore.ieee.org/abstract/document/8320514

Fachdidaktische Analysekompetenz zum Umgang mit Darstellungen – Vignettenbasierte Erhebung mit Texten, Comics und Videos

Setzt man Vignetten zur Kompetenzmessung bei Lehramtsstudierenden und praktizierenden Lehrkräften ein, wird durch den Bezug zu konkreten Situationen eine unterrichtsnahe Erhebung fachdidaktischer Kompetenzaspekte ermöglicht. Für die inhaltsbereichsspezifische Messung fachdidaktischer Analysekompetenz zum Umgang mit Darstellungen werden im Folgenden theoretische Grundlagen skizziert, verschiedene Erhebungsformate diskutiert und ein entsprechendes Forschungsdesign vorgestellt

On continuum modeling of sputter erosion under normal incidence: interplay between nonlocality and nonlinearity

Under specific experimental circumstances, sputter erosion on semiconductor materials exhibits highly ordered hexagonal dot-like nanostructures. In a recent attempt to theoretically understand this pattern forming process, Facsko et al. [Phys. Rev. B 69, 153412 (2004)] suggested a nonlocal, damped Kuramoto-Sivashinsky equation as a potential candidate for an adequate continuum model of this self-organizing process. In this study we theoretically investigate this proposal by (i) formally deriving such a nonlocal equation as minimal model from balance considerations, (ii) showing that it can be exactly mapped to a local, damped Kuramoto-Sivashinsky equation, and (iii) inspecting the consequences of the resulting non-stationary erosion dynamics.Comment: 7 pages, 2 Postscript figures, accepted by Phys. Rev. B corrected typos, few minor change

Automated root cause isolation in performance regression testing

Testing of software is an important aspect of software development. There exist multiple kinds of tests, like unit tests and integration tests. The tests this thesis will focus on will be load tests, which are used to observe a system’s behavior under load. The presented approach will use these load tests in order to observe and analyze the performance of a system, like e.g. the response times of methods. Next these observations are compared with those made on other versions of the system, in order to detect performance regressions, deteriorations in performance, between versions. Another goal of the approach will be to identify the root cause of the regressions, which is the source code change responsible for introducing them. By doing this, the task of fixing this problem will be made easier for the software engineer, since he has an entry point for the problem.Das Testen von Software ist ein wichtiger Bestandteil der Software-Entwicklung. Es existieren viele Arten von Tests, wie Unit-Tests und Integrationstests. Die Tests, auf welche sich diese Thesis fokussiert, sind Lasttests. Diese werden genutzt um zu beobachten, wie ein System sich unter Belastung verhält. Der vorgestellte Ansatz wird diese Lasttests nutzen, um das Betriebsverhalten eines Systems zu erfassen und analysieren, wie z.B. das Antwortzeitverhalten von einzelnen Methoden. Als Nächstes werden diese Beobachtungen mit denen verglichen, die auf anderen Versionen des Systems gemacht wurden, um Regressionen im Betriebsverhalten, wie Verschlechterungen des Antwortzeitverhaltens, zwischen den Versionen zu finden. Ein weiteres Ziel des Ansatzes wird es sein, die Hauptursache einer Regression zu identifizieren, welches die Quellcodeänderung ist, die für die Einführung der Regression verantwortlich ist. Dies wird es dem Software-Entwickler, der beauftragt wurde die Regression zu verbessern, einfacher machen dies zu tun, da er bereits einen festen Ansatzpunkt geliefert bekommen hat