Search results for "virtu"
showing 10 items of 1987 documents
Immersive Virtual Reality for Cultural Heritage Exploration
2023
Virtual Reality can provide an immersive experience that allows cultural heritage to be experienced in a more realistic and immersive way than traditional showcasing techniques. The objective of this paper is to provide a software pipeline that can be adopted for the realization of immersive experiences in cultural heritage sites. This work has been realized within the 3DLab-Sicilia project, which includes the realization of immersive virtual tours of UNESCO World Heritage sites located in the Sicily area (Italy).
Question Answering with BERT: designing a 3D virtual avatar for Cultural Heritage exploration
2022
Recent technological developments are changing how people experience physical and virtual environments. Technologies like Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR), today, are impacting daily life and are being used in various domains including Cultural Heritage. Applying intelligence to applications using these technologies, through AI and Deep Learning can provide a more immersive user experience. In this paper, we propose the design of a system that realize an avatar with question-answering capabilities, for the specific purpose of giving help in immersive navigation of cultural heritage sites. It is based on a BERT model tailored to the Italian language and wi…
Virtual Element based formulations for computational materials micro-mechanics and homogenization
2021
In this thesis, a computational framework for microstructural modelling of transverse behaviour of heterogeneous materials is presented. The context of this research is part of the broad and active field of Computational Micromechanics, which has emerged as an effective tool both to understand the influence of complex microstructure on the macro-mechanical response of engineering materials and to tailor-design innovative materials for specific applications through a proper modification of their microstructure. While the classical continuum approximation does not account for microstructural details within the material, computational micromechanics allows detailed modelling of a heterogeneous…
Virtual Element Method: Micro-Mechanics Applications
2020
In this contribution we present an application of the lowest order Virtual Element Method (VEM) to the problem of material computational homogenization. Material homogenization allows retrieving material properties through suitable volume averaging procedures, starting from a detailed representation of the micro-constituents of the considered material. The representation of such microstructure constitutes a remarkable effort in terms of data/mesh preparation, especially when there is not evident microstructural regularity. For such a reason, computational micromechanics may represent a challenging benchmark for showing the potential of VEM. In this contribution, polycrystalline materials ar…
Stability of Microgrids: An Application of Virtual Synchronous Generator
2022
The objective of this paper is to illustrate an alternative control algorithm for power converters which have the task of introducing the energy generated by systems based on the use of renewable sources such as, photovoltaic or wind power, in to small-sized networks, microgrids. Virtual Synchronous Generator can operate both in parallel to the main network as well as in isolated and autonomous conditions (islanding-mode). The contribute of this work is to drive a consolidate approach, made in time domain, in a more flexible and less time-consuming approach based on Park transformation.
Frequency Dynamics in Fully Non-Synchronous Electrical Grids: A Case Study of an Existing Island
2022
The operation of a power system with 100% converter-interfaced generation poses several questions and challenges regarding various aspects of the design and the control of the system. Existing literature on the integration of renewable energy sources in isolated systems mainly focuses on energy aspects or steady-state issues, and only a few studies examine the dynamic issues of autonomous networks operated with fully non-synchronous generation. A lack of research can be found in particular in the determination of the required amount of grid-forming power, the selection of the number and rated power of the units which should implement the grid-forming controls, and the relative locations of …
Synchronizing Interactions Between Different Types of Grid-Forming Converters in Smart Grids
2022
The work investigates the transient synchronizing interactions between different types of grid-forming controls. Two well-known grid-forming schemes are implemented and considered for analysis: a droop-based control and a swing-based control. The two controls are examined for a temporary loss of synchronism. The analysis is performed considering two different conditions for the grid interconnecting the converters: a resistive-inductive grid and a mainly inductive grid. The first case corresponds to actual conditions in low and medium voltage applications. The second case is realized with the implementation of a virtual reactance in the grid-forming control scheme. The analysis of the result…
A Study of Power-Frequency Dynamics in Isolated Power Networks with 100% Converter-Interfaced Generation
2020
The operation of a system with 100% converter-interfaced generation poses several questions and challenges regarding various aspects of the dynamic characteristics of the system. The effects related to the power-frequency control are among the most relevant issues which need to be investigated. The paper takes into examination the case of an existing isolated power network of a geographical island assuming a completely converter-interfaced generation. The factors playing a fundamental role in the assessment of which sources should be designated to be grid-forming are identified with a small signal model formulation of a generic multiple oscillators system. Simulations and analysis performed…
Grid-Forming Converters in Weak Grids – The Case of a Mediterranean Island
2019
The existing power network of a Mediterranean island is used as test bed for the study of grid-forming converter dynamics in weak grid conditions. The control scheme adopted for the converter falls in the category of the so called virtual synchronous machines (VSM). Particular attention is committed to the interaction between the converter controls and the synchronous machines dynamics. Time delays typically associated to measurements and filters are considered in the study, and included in the system model with a specific mathematical approach. Time-domain simulations show the occurrence of oscillatory instability in the system, with VSM and synchronous machines swinging against each other…