42 research outputs found

    Reusing Test-Cases on Different Levels of Abstraction in a Model Based Development Tool

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    Seamless model based development aims to use models during all phases of the development process of a system. During the development process in a component-based approach, components of a system are described at qualitatively differing abstraction levels: during requirements engineering component models are rather abstract high-level and underspecified, while during implementation the component models are rather concrete and fully specified in order to enable code generation. An important issue that arises is assuring that the concrete models correspond to abstract models. In this paper, we propose a method to assure that concrete models for system components refine more abstract models for the same components. In particular we advocate a framework for reusing testcases at different abstraction levels. Our approach, even if it cannot completely prove the refinement, can be used to ensure confidence in the development process. In particular we are targeting the refinement of requirements which are represented as very abstract models. Besides a formal model of our approach, we discuss our experiences with the development of an Adaptive Cruise Control (ACC) system in a model driven development process. This uses extensions which we implemented for our model-based development tool and which are briefly presented in this paper.Comment: In Proceedings MBT 2012, arXiv:1202.582

    Fano interference in quantum resonances from angle-resolved elastic scattering

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    Asymmetric spectral line shapes are a hallmark of interference of a quasi-bound state with a continuum of states. Such line shapes are well known for multichannel systems, for example, in photoionization or Feshbach resonances in molecular scattering. On the other hand, in resonant single channel scattering, the signature of such interference may disappear due to the orthogonality of partial waves. Here, we show that probing the angular dependence of the cross section allows us to unveil asymmetric Fano profiles also in a single channel shape resonance. We observe a shift in the peak of the resonance profile in the elastic collisions between metastable helium and deuterium molecules with detection angle, in excellent agreement with theoretical predictions from full quantum scattering calculations. Using a model description for the partial wave interference, we can disentangle the resonant and background contributions and extract the relative phase responsible for the characteristic Fano-like profiles from our experimental measurements

    Continuum-electron interferometry for enhancement of photoelectron circular dichroism and measurement of bound, free, and mixed contributions to chiral response

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    We develop photoelectron interferometry based on laser-assisted extreme ultraviolet ionization for flexible and robust control of photoelectron circular dichroism in randomly oriented chiral molecules. A comb of XUV photons ionizes a sample of chiral molecules in the presence of a time-delayed infrared or visible laser pulse promoting interferences between components of the XUV-ionized photoelectron wave packet. In striking contrast to multicolor phase control schemes relying on pulse shaping techniques, the magnitude of the resulting chiral signal is here controlled by the time delay between the XUV and laser pulses. Furthermore, we show that the relative polarization configurations of the XUV and IR fields allows for disentangling the contributions of bound and continuum states to the chiral response. Our proposal provides a simple, robust and versatile tool for the control of photoelectron circular dichroism and experimentally feasible protocol for probing the individual contributions of bound and continuum states to the PECD in a time-resolved manner

    Quantum control of ro-vibrational dynamics and application to light-induced molecular chirality

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    Achiral molecules can be made temporarily chiral by excitation with electric fields, in the sense that an average over molecular orientations displays a net chiral signal [Tikhonov et al., Sci. Adv. 8, eade0311 (2022)]. Here, we go beyond the assumption of molecular orientations to remain fixed during the excitation process. Treating both rotations and vibrations quantum mechanically, we identify conditions for the creation of chiral vibrational wavepackets -- with net chiral signals -- in ensembles of achiral molecules which are initially randomly oriented. Based on the analysis of symmetry and controllability, we derive excitation schemes for the creation of chiral wavepackets using a combination of (a) microwave and IR pulses and (b) a static field and a sequence of IR pulses. These protocols leverage quantum rotational dynamics for pump-probe spectroscopy of chiral vibrational dynamics, extending the latter to regions of the electromagnetic spectrum other than the UV.Comment: 16 pages, 8 figure

    Phase protection of Fano-Feshbach resonances

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    Decay of bound states due to coupling with free particle states is a general phenomenon occurring at energy scales from MeV in nuclear physics to peV in ultracold atomic gases. Such a coupling gives rise to Fano-Feshbach resonances (FFR) that have become key to understanding and controlling interactions—in ultracold atomic gases, but also between quasiparticles, such as microcavity polaritons. Their energy positions were shown to follow quantum chaotic statistics. In contrast, their lifetimes have so far escaped a similarly comprehensive understanding. Here, we show that bound states, despite being resonantly coupled to a scattering state, become protected from decay whenever the relative phase is a multiple of π. We observe this phenomenon by measuring lifetimes spanning four orders of magnitude for FFR of spin–orbit excited molecular ions with merged beam and electrostatic trap experiments. Our results provide a blueprint for identifying naturally long-lived states in a decaying quantum system

    Intelligente Vernetzung zur autonomen Fräsbearbeitung von Strukturbauteilen - Ergebnisbericht des BMBF Verbundprojektes TensorMill

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    Digitalisierte Prozesse können zukünftig zu einer intelligenten Fertigung beitragen, um den Herausforderungen einer intelligent vernetzten, autonomen Fertigung von sicherheitsrelevanten Integralbauteilen zu begegnen. Die Herausforderungen hierbei liegen insbesondere in der Aufzeichnung und Extraktion von nutzerrelevanten Daten zur Steigerung der Produktivität bei der Fertigung von sicherheitsrelevanten Integralbauteilen für die Luft- und Raumfahrtbranche. An diesem Punkt hat das Verbundforschungsprojekt „TensorMill“ angesetzt. Ziel des Projekts war es, die Produktivität in der spanenden Fertigung sicherheitsrelevanter Integralbauteile durch die Entwicklung und den Aufbau einer intelligent, vernetzten, autonomen Fertigung zu erhöhen und die Prozesssicherheit zu verbessern. Die intelligente Fertigung soll dabei in der Lage sein, auf möglichst viele Situationen im Fertigungsprozess mit Hilfe von künstlicher Intelligenz (KI) zu reagieren. Für die Implementierung der KI-basierten Lösungen sind im Projekt fortschrittliche Methoden und Vorgehensweisen entstanden, welche es ermöglichen, die Daten von Produktionsmitteln in einer einfachen Form nutzbar zu machen, damit diese einen Mehrwert für Hersteller und Anwender bringen. Die aufbereiteten Daten dienten schließlich der Umsetzung von KI-basierten Lösungen zur prozessparallelen Qualitätsprognose und Werkzeugzustandserkennung. Darüber hinaus wurde ein entwickeltes cyber-physisches Spannsystem entwickelt, um neuartige Ansätze zur Abdrängungskompensation und Echtzeitbewertung der Prozessstabilität zu erforschen

    Game laboratory studies

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    Prof. Dr. Jens Schröter ist Herausgeber der Reihe und die Herausgeber der einzelnen Hefte sind renommierte Wissenschaftler und -innen aus dem In- und Ausland.Um die Analyse von Computerspielen aus produktionsästhetischer Perspektive zu erproben, lehnt sich der vorliegende Band an die Akteur-Netzwerk-Theorie (ANT) an. Mit ihr geht es ihm um die Frage nach den Aktanten des Game Design – etwa: Welche Hard- und Softwarekomponenten kommen wann und wofür zum Einsatz; wie und mittels welcher Medien notieren Level-Designer ihre Ideen, und wie werden die Aufzeichnungen später von Programmierern implementiert; und welche Rolle spielt eigentlich eine Action-Figur auf dem Schreibtisch eines Textur-Artists
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