| 1. |
- Krticka, J., et al.
(författare)
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HST/STIS analysis of the first main sequence pulsar CU Virginis
- 2019
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 625
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Tidskriftsartikel (refereegranskat)abstract
- ContextCU Vir has been the first main sequence star that showed regular radio pulses that persist for decades, resembling the radio lighthouse of pulsars and interpreted as auroral radio emission similar to that found in planets. The star belongs to a rare group of magnetic chemically peculiar stars with variable rotational period.AimsWe study the ultraviolet (UV) spectrum of CU Vir obtained using STIS spectrograph onboard the Hubble Space Telescope (HST) to search for the source of radio emission and to test the model of the rotational period evolution. Methods. We used our own far-UV and visual photometric observations supplemented with the archival data to improve the parameters of the quasisinusoidal long-term variations of the rotational period. We predict the flux variations of CU Vir from surface abundance maps and compare these variations with UV flux distribution. We searched for wind, auroral, and interstellar lines in the spectra.ResultsThe UV and visual light curves display the same long-term period variations supporting their common origin. New updated abundance maps provide better agreement with the observed flux distribution. The upper limit of the wind mass-loss rate is about 10(-12) M-circle dot yr(-1). We do not find any auroral lines. We find rotationally modulated variability of interstellar lines, which is most likely of instrumental origin.ConclusionsOur analysis supports the flux redistribution from far-UV to near-UV and visual domains originating in surface abundance spots as the main cause of the flux variability in chemically peculiar stars. Therefore, UV and optical variations are related and the structures leading to these variations are rigidly confined to the stellar surface. The radio emission of CU Vir is most likely powered by a very weak presumably purely metallic wind, which leaves no imprint in spectra.
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| 2. |
- Bordeleau, Francis, et al.
(författare)
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Challenges and Research Directions for Successfully Applying MBE Tools in Practice
- 2017
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Ingår i: CEUR Workshop Proceedings. - 1613-0073.
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Konferensbidrag (refereegranskat)abstract
- Model Based Engineering aims to improve efficiency and effectiveness of software engineering. Success in industrial practice of MBE does not only depend on the modeling languages and constructive or analytical approaches, like code generation or model checking. It is also heavily influenced by the quality and, particularly, usability of the used tools. In this position paper, we discuss challenges experienced in applying MBE in practice both from academic as well as industrial viewpoints. Based on the research challenges, we discuss future research directions to improve the chances for the success of MBE in industrial practice.
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| 3. |
- Karg, Stefan, et al.
(författare)
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Model-Driven Software Engineering in the open ETCS Project: Project Experiences and Lessons Learned
- 2016
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Ingår i: Proceedings of 19th International Conference on Model-Driven Engineering Languages and Systems. - New York, NY, USA : ACM. ; , s. 238-248
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Konferensbidrag (refereegranskat)abstract
- Model-driven software engineering in industrial practice has been the focus of different empirical studies and experience reports. Particularly, positive effects of model-driven software engineering have been reported in the domain of embedded and safety-critical systems. We report in this paper on the experiences of the openETCS European research project whose goal was to formalize the System Requirements Specification and to develop an open source reference implementation of the European Train Control System including open source modeling tools. Furthermore, we will discuss lessons learned, e.g., about using open source modeling toolchains in safety-critical contexts and about using the SCADE Suite for the development of the safety-critical parts.
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| 4. |
- Vogel-Heuser, B., et al.
(författare)
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Selected challenges of software evolution for automated production systems
- 2015
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Ingår i: 13th International Conference on Industrial Informatics, INDIN 2015, Robinson College, Cambridge, United Kingdom, 22 - 24 July 2015. - : IEEE. - 9781479966493
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Konferensbidrag (refereegranskat)abstract
- Automated machines and plants are operated for some decades and undergo an everlasting evolution during this time. In this paper, we present three related open evolution challenges focusing on software evolution in the domain of automated production systems, i.e. evolution and co-evolution of (interdisciplinary) engineering models and code, quality assurance as well as variant and version management during evolution.
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