Gearing up the SPHERE

Direct imaging and spectral characterisation of exoplanets is one of the most exciting, but also one of the most challenging areas, in modern astronomy. The challenge is to overcome the very large contrast between the host star and its planet seen at very small angular separations. This article reports on the progress made in the construction of the second generation VLT instrument SPHERE, the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument. SPHERE is expected to be commissioned on the VLT in 2013

Non Common Path Aberrations Correction

The primary goal of this thesis was the correction of Non-Common-Path-Aberrations in the SPHERE instrument for helping it meeting its contrast requirements. SPHERE's purpose is the search and characterization of giant exo-planets around nearby stars. The author implemented a method called Electric Field Conjugation that he tested in simulation as well as on the real system. A full week was booked in SPHERE schedule a few days before the second commissioning in June 2014. It gave the opportunity to the author to travel to the VLT in Chile and experiment directly on the system. The contrast gain objective of another order of magnitude in a medium-sized area has successfully been reached bringing SPHERE raw speckle contrast from about $10^{-6}$ to $10^{-7}$. The algorithm has therefore proven its value and will be further investigated and hopefully automated by the SPHERE team based on the codes developed by the author. However it is important to keep in mind that Electric Field Conjugation is more effective for follow-up studies in order to improve the quality of the observations. Indeed the area for a good correction is very limited. It can't be used for exo-planets discovery unless the corrected area is made big enough but the performance will be less.Comment: Projet de fin d'\'etudes 2014, ISAE-Supaer

Nanoparticle Counts Emissions of Trucks: EURO 3 with and without DPF Compared to EURO 4 and EURO 5

Investigations of emissions from three modern HD vehicles (HDV) were carried out on a chassis-dynamometer. One of the vehicles uses PM-Kat and is certified according to EURO4. The second one is EURO5 compliant and uses SCR. The third one is was a EURO3 HDV, which was tested with and without VERT-certified DPF. The investigation focussed on solid particles in the mobility size range of 10-400nm. The instruments were SMPS, NanoMet, PASS and ELPI. Sampling conformed to PMP for SMPS and NanoMet, PASS and ELPI were used with FPS-dilution. Metallic emissions were measured using ICP-MS. Also measured were inherent secondary emissions, especially NO2 and NH3. Compared to EURO3 without DPF a moderate curtailment of nanoparticle emissions was observed for the majority of operating points for EURO4 with PM-Kat and EURO5 with SCR. However, at full load the EURO5 engine emitted higher concentrations than a EURO3 engine without DPF. A stochastic particle release was observed from the PM-Kat of the EURO4 engine. Its penetration scatter was very much dependant on the soot burden and the testing history. Compared to a EURO3 engine with a DPF conforming to VERT criteria, both modern engines EURO4 and EURO5 emitted 100-500 times more nanoparticles. Very good results of the gaseous emissions – a significant reduction of NOx – showed the EURO5 engine. There were no deleterious effects observed due to the SCR. The concentrations of NH3 and N2O remained close to the detection limit. However, the EURO4 engine emitted rather high concentrations of NO2 at about half load range. Emissions of Vanadium with EURO5 and Platinum with EURO4 were low in both cases, even below detection limit

Managing rapport in talk: using rapport sensitive incidents to explore the motivational concerns underlying the management of relations

This paper focuses on the motivational concerns that underlie the management of relations. In linguistics, the management of relations has been discussed extensively within politeness theory, and so the paper starts by identifying four key issues of controversy in politeness theory: (a) should ‘polite’ language use be explained in terms of face (e.g. Brown, Penelope, Levinson, Stephen C., 1987. Politeness. Some Universals in Language Usage, CUP, Cambridge. [Originally published as Universals in Language Usage: Politeness Phenomenon. In: Goody, Esther, (Ed.), Questions and Politeness: Strategies in Social Interaction. CUP, New York, 1978), conversational maxims (e.g. Leech, Geoffrey N., 1983. Principles of Pragmatics. Longman, London), and/or conversational rights (e.g. Fraser, Bruce, 1990. Perspectives on politeness. Journal of Pragmatics 14 (2), 219–236); (b) why are speech acts such as orders interpersonally sensitive — is it because they are a threat to our autonomy (Brown and Levinson, 1987 [1978]), or because of cost–benefit concerns (Leech, 1983); (c) is Brown and Levinson's concept of negative face too individually focused, and should a social identity component be included (Matsumoto, Yoshiko, 1988. Reexamination of the universality of face: politeness phenomena in Japanese. Journal of Pragmatics 12, 403–426); and (d) is face just a personal/individual concern or can it be a group concern (Gao, Ge, 1996. Self and other: a Chinese perspective on interpersonal relationships. In: Gudykunst, W.B., Ting-Toomey, S., Nishida, T. (Eds.), Communication in Personal Relationships Across Cultures, Sage, London. pp. 81–101.)? The paper then uses reports of authentic rapport sensitive incidents to throw light on these controversial issues and to find out the relational management concerns that people perceive in their everyday lives. It maintains that such data is important to politeness theory, because linguistic politeness needs to be studied within the situated social psychological context in which it occurs. The paper ends by presenting and arguing for a conceptual framework that draws a fundamental distinction between face and sociality rights, and that incorporates an independent/interdependent perspective, thus providing a more comprehensive framework for analysing the management of relations than is currently available

Ein zielsystemidentischer Ansatz für das domänenspezifische Rapid Prototyping in der Informations- und Elektrotechnik

The systematic reuse of experiences and results gained during the development of production projects is possible by partitioning control system hardware and software, as well as by introducing appropriate interfaces. Suppliers will be able to share this yield of hardware and software components for example with vehicle manufacturers (OEMs). By sharing these components, suppliers will be able to share their experience and expertise gained through the development of production proven control systems without compromising their proprietary know- how. Thus OEMs and system suppliers can engage in efficient simultaneous component engineering. This approach will enable OEMs to quickly implement innovations within their own organizations and beat their competitors to the market. Furthermore, this reuse of experiences and results from production development facilitates and accelerates the creation of prototypes that are essentially identical to the target system and can therefore be readily used in the original environment. The development effort can thus be focused on new concepts and components, which in turn will enable a much earlier evaluation of feasibility and acceptance. Thus duplication and parallel development can be reduced to a minimum. Compared to traditional approaches, this approach will reduce overall development time. By using hardware with reconfigurable logic, rather than static hardware, modifications and extensions become possible and are easy and fast. Also, in traditional development, the decision as to where to implement a given function - in the microcontroller, in the reconfigurable logic or distributed between both units - has to be made very early, when not all information is available yet. Embedding the microcontroller in reconfigurable logic, however, lets developers postpone this decision until very late in development, when it can be made with much greater confidence. The functions realized in the reconfigurable logic can be used, for example, as executable specifications for ASIC (Application-specific Integrated Circuit) developments. The results obtained during development of the user software can be reused in the production system without much extra cost, since the user interface software accesses hardware drivers, service routines and the operating system via target system identical interfaces. Consistently using graphic development tools capable of automatic code generation for prototype and production systems, as well as other tools that can be used to automate manual, error-prone steps in the development process, will further reduce development time. This thesis describes target-identical domain-specific rapid prototyping using a development ECU for diesel engines as a sample application.In der vorliegenden Arbeit wird ein zielsystemidentischer Ansatz für das domänenspezifische Rapid Prototyping in der Informations- und Elektrotechnik vorgestellt. Dabei wird durch die Partionierung von Serienstrukturen sowohl der Hardware, als auch der Software, in unabhängige Teilkomponenten sowie der Einführung entsprechender Schnittstellen die Wiederverwendung von Erfahrungen aus Serienentwicklungen systematisch ermöglicht. Dadurch können, die bislang den Systemlieferanten vorbehaltenen Erfahrungen aus Serienentwicklungen in gut handhabbarer Form z.B. Fahrzeugherstellern (OEM) für Forschungs- und Entwicklungsaufgaben zur Verfügung gestellt werden, ohne dass die Systemlieferanten ihr Know-How offen legen müssen. Es wird damit eine effiziente Möglichkeit für das Simultaneous Engineering zwischen OEM und Systemlieferant ermöglicht. Des Weiteren kann mit Hilfe der Wiederverwendung von Erfahrungen aus Serienentwicklungen sehr schnell ein in wesentlichen Punkten mit dem Zielsystem identischer Prototyp erstellt und in der realen Umgebung eingesetzt werden. Der Entwicklungsaufwand kann damit auf neue Konzepte und Komponenten begrenzt und somit eine frühe Aussage über Realisierbarkeit und Akzeptanz getroffen werden. Dadurch lassen sich Doppel- und Parallelentwicklungen auf ein Minimum reduzieren und damit die Entwicklungszeit gegenüber traditionellen Verfahren deutlich verkürzen. Durch den Einsatz rekonfigurierbarer Logik wird es ermöglicht, Änderungen in der normalerweise statischen Hardware vorzunehmen. Zusätzlich kann durch Einbetten des Mikrocontrollers in die rekonfigurierbare Logik die normalerweise sehr früh zu treffende Entscheidung, ob eine Funktion im Mikrocontroller oder in der rekonfigurierbaren Logik realisiert werden soll, noch in sehr fortgeschrittenen Entwicklungsphasen beeinflusst werden. Die in der rekonfigurierbaren Logik umgesetzten Funktionen können anschließend als ausführbare Spezifikation für ASIC Entwicklungen verwendet werden. Die bei der Entwicklung der Anwendersoftware erzielten Ergebnisse können ohne großen Aufwand im Seriensystem weiterverwendet werden, da die Anwendersoftware nur über mit dem Zielsystem identische Schnittstellen auf Hardwaretreiber, Service Routinen sowie das Betriebssystem zugreift. Durch die Steigerung des Automatisierungsgrades z.B. mit Hilfe der Verwendung von grafischen Entwicklungswerkzeugen mit automatischer Codegenerierung können die Entwicklung beschleunigt, Fehlerquellen reduziert und somit die Qualität verbessert werden. Der in der vorliegenden Arbeit beschriebene zielsystemidentische Ansatz für das domänenspezifische Rapid Prototyping wird am Beispiel eines Entwicklungs-Steuergerätes für Dieselmotoren dargestellt

Adaptive optics control using model-based reinforcement learning

Reinforcement learning (RL) presents a new approach for controlling adaptive optics (AO) systems for Astronomy. It promises to effectively cope with some aspects often hampering AO performance such as temporal delay or calibration errors. We formulate the AO control loop as a model-based RL problem (MBRL) and apply it in numerical simulations to a simple Shack-Hartmann Sensor (SHS) based AO system with 24 resolution elements across the aperture. The simulations show that MBRL controlled AO predicts the temporal evolution of turbulence and adjusts to mis-registration between deformable mirror and SHS which is a typical calibration issue in AO. The method learns continuously on timescales of some seconds and is therefore capable of automatically adjusting to changing conditions. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing AgreementPeer reviewe

Optimierung einer adaptiven Optik und ihre Anwendung in der ortsaufgelösten Spektroskopie von T Tauri

Das AO System ALFA der Max-Planck Institute für Astronomie und für extraterrestrische Physik basiert auf einem Shack-Hartmann-Wellenfrontsensor und ist eines der wenigen Systeme weltweit, die mit einem Laserleitstern ausgerüstet sind. Die effektive Verwendung sowohl leuchtschwacher natürlicher Leitsterne als auch des Laserleitsterns erfordert optimierte Algorithmen für die Wellenfront-Rekonstruktion. der Algorithmus zur Bestimmung der Intensitätsschwerpunkte wurde durch Ausblendung unwesentlicher Pixel und durch Gewichtung der Intensitäten entsprechend ihrem Signal-Rausch-Verhältnis verbessert. Zur Rekonstruktion der Wellenfront aus den Sensordaten wurden sowohl ein modifizierter Least-Squares als auch ein Maximum a Posteriori Algorithmus entwickelt. Zudem wird eine neue Mikrolinsengeometrie vorgestellt, die optimal an die ringförmige Teleskoppupille angepasst ist. Die neuen Methoden wurden simuliert, in ALFA implementiert und am Teleskop getestet. Sie führten zu einer Steigerung der Grenzhelligkeit der benutzbaren Leitsterne von ca. V = 11 auf V = 14 bei sehr guten Beobachtungsbedingungen. Die Analyse zeigt, daß eine weitere Steigerung um etwa eine halbe Magnitude durch einen rauschfreien Wellenfrontsensor möglich wäre. Des weiteren wurden neue Beobachtungsmethoden in Verbindung mit AO verwendet, um das junge Sternsystem T Tauri zu untersuchen. Durch räumlich hochaufgelöste Spektroskopie gelang es, die Nahinfrarotspektren der Komponenten T Tau N und T Tau S zu bestimmen. Beide Sterne zeigen ein ähnliches Emissionslinienspektrum, und T Tau S weist keine für stellare Photosphären üblichen Merkmale auf. Durch AO-kompensierte Speckle-Interferometrie wurde die Existenz des kürzlich entdeckten Begleiters von T Tau S im Abstand von nur 0.08' bestätigt. Unter Verwendung bereits publizierter Daten wurden die Bahnparameter weiter eingeengt, die auf eine Masse von zwei Sonnenmassen für T Tau S hindeuten