1,086 research outputs found
Distributed robotic autonomous control for observatory systems (DRACOS)
No full textThe rapid growth of time-domain sky surveys has made it increasingly important to have robotic observatories that can operate reliably without human intervention. Yet, much of today's obser- vatory control software still depends on fragmented, vendor-specific tools and often lacks the strong architectural foundations needed to handle the challenges of fully unattended operation, particularly in terms of concurrency, safety, and modularity. This thesis addresses these gaps by introducing the Distributed Robotic Autonomous Control for Observatory Systems (DRACOS), a unified control framework designed to deliver a robust and extensible solution for autonomous observatory management. DRACOS is built on the Robot Op- erating System 2 (ROS 2), applying modern robotics principles to astronomy in a systematic way. At its core is a hierarchical, agent-based architecture that combines a clear chain of command with a distributed network of modular software agents. A central innovation is the Subsystem Agent Contract, which requires all hardware interfaces to be implemented as ROS 2 Lifecycle Nodes ensuring deterministic, system-wide state management that is essential for dependable autonomous operations. Instead of relying on traditional procedural scripts, DRACOS uses Behavior Trees to model com- plex, reactive tasks. This approach integrates error handling and recovery directly into task exe- cution and is backed by a high-priority, event-driven safety system capable of instantly halting all activities in response to critical events. The framework also includes a web-based user interface and has been validated through a test campaign, using both industry-standard simulators and real-world on-sky trials with the new 0.4 m TRAC robotic telescope at the Montsec Observatory. Results show that DRACOS meets its requirements for reliability, safety, and performance, successfully achieving fully autonomous op- eration. Overall, this work positions DRACOS as both a practical solution for today's observatories and an architectural blueprint for the next generation of robotic astronomy facilities.9 - Indústria, Innovació i Infraestructur
Tagging the s quark in hadronic decays of the Z
No full textThe DELPHI detector at LEP is equipped with RICH detectors which can be exploited for tagging decays of the Z boson into pairs, High momentum K-+/- identified with the RICH have been used both for a double tag of the s quark and for a single tag using the phi(1020) meson
Measurement of the strange quark asymmetry at the Z(0) peak using high energy charged kaons identified by the DELPHI ring imaging Cherenkov detector
No full textA comparison of the forward-backward s-quark asymmetry with the b-quark asymmetry can be used to test the universality of the standard model coupling constants, We present a measurement of the s-quark asymmetry at the Z(o) peak using high energy charged kaons identified by the DELPHI ring imaging Cherenkov detector
Measurement of the B semileptonic branching fraction into excited charm mesons
No full textA study of B semileptonic decays into D, D pi /sup +or-/ and D* pi /sup +or-/ final states is presented. The D/sup 0/, D/sup +/ and D* /sup +/ are exclusively reconstructed using Z decays data recorded from 1992 to 1995 in the DELPHI experiment at LEP. (5 refs)
A muon telescope as demonstrator of the juno top tracker detector
No full textA four-layer muon telescope has been built, employing the equipment and electronics developed for the Top Tracker (TT) detector of the Jiangmen Underground Neutrino Observatory (JUNO). It will serve as a demonstrator of the hardware capabilities in terms of detection efficiency, processing power and system reliability. The entire readout, trigger and acquisition systems have been conceived and built around versatile modular electronics embedding the latest generation of system on chips. A detailed description of the telescope will be given along with the status of the TT electronics and their preliminary validation tests
Investigation of Unsteady Flow Fields in Wind Tunnels by Means of Particle Image Velocimetry
No full textParticle Image Velocimetry (PIV) is increasingly used to investigate unsteady velocity fields instantaneously. For the first time the PIV technique allows the recording of a complete velocity field in a plane of the flow within microseconds. PIV provides information aboutunsteady flow fields which is difficult to obtain with other experimental techniques. It also helps to save operational time in the wind tunnel. At DLR a set up for PIV has been developed which can be operated under the rough environmental conditions (noise, vibrations) of a large industrial wind tunnel. This system has been successfully applied to very low speed as well as to high speed flows(Uc. 600 m/s). The evaluation and post-processing of the PIV recordings run fully automated on a workstation
Damage surrogate models for real-time flooding risk assessment of passenger ships
No full textReal-time assessment of flooding risk associated with the collision between two ships, requires a fast estimation of damage dimensions and associated survivability. The state-of-the-art frameworks for risk assessment on passenger ships do not consider a direct evaluation of damages through crash simulations but refer to probabilistic considerations, modelling damage characteristics according to statutory marginal distributions of damage breaches too old to be any longer relevant. In any case, such an approach is not possible for the real-time risk assessment process developed in project FLARE, aimed at promoting the employment of first-principles tools for risk evaluation. In this spirit, the present work investigates the possibility of developing a database-oriented damage breach model, which employs direct crash analyses with the super-element code SHARP. However, the sole usage of crash simulations is not suitable for real-time applications. Therefore, starting from the collision simulation database, surrogate models have to be derived for real-time application. In this specific case, three different strategies have been used for the models creation namely: multiple linear regressions, neural networks and decision trees. Here, the strategy to build the database and application on a reference passenger ship is described, highlighting the differences in accuracy and calculation time between the proposed surrogate models.Ship Design, Production and Operation
The effect of the operational environment on the survivability of passenger ships
No full textThe in-force probabilistic framework for passenger ship survivability assessment covers collision hazards. The framework primarily pertains to a static approach. Nonetheless, more complex dynamic analyses usually employ the same damage definitions, adding besides the breach characteristics, the environmental condition selection or, more precisely, the irregular wave environment necessary to simulate the damage scenarios. The traditional dynamic approaches to survivability consider only the significant wave height sampled from statistical formulations, with the wave period deriving from a constant steepness assumption. However, wave height and period influence ship dynamics in waves differently, especially concerning survivability after damage. Therefore, aiming at a direct assessment of ship survivability and the probability of loss of lives determination in realistic operational scenarios, it is essential to properly study the influence of combined variations of wave height and periods and their occurrence. The present study proposes a methodology for dynamic simulations in site-specific conditions derived from the Global Wave Statistics. The study documents the process in two critical collision damages for a reference passenger ship, using wave height and period combinations typical of the main sea areas of interest for passenger ships and performing a sensitivity analysis on the simulations needed to evaluate survivability. This enhanced analysis allows identifying the limiting environmental conditions for the critical damage cases, including the effect of heading variations, determining the ship's survivability to specific damage in an operational area.</p
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