On the path of Exploratory Search Users - A Semantic Web tool

L’Exploratory Search, paradigma di ricerca basato sulle attività di scoperta e d’apprendimento, è stato per diverso tempo ignorato dai motori di ricerca tradizionali. Invece, è spesso dalle ricerche esplorative che nascono le idee più innovative. Le recenti tecnologie del Semantic Web forniscono le soluzioni che permettono d’implementare dei motori di ricerca capaci di accompagnare gli utenti impegnati in tale tipo di ricerca. Aemoo, motore di ricerca sul quale s’appoggia questa tesi ne è un esempio efficace. A partire da quest’ultimo e sempre con l’aiuto delle tecnologie del Web of Data, questo lavoro si propone di fornire una metodologia che permette di prendere in considerazione la singolarità del profilo di ciascun utente al fine di guidarlo nella sua ricerca esplorativa in modo personalizzato. Il criterio di personalizzazione che abbiamo scelto è comportamentale, ovvero basato sulle decisioni che l’utente prende ad ogni tappa che ritma il processo di ricerca. Implementando un prototipo, abbiamo potuto testare la validità di quest’approccio permettendo quindi all’utente di non essere più solo nel lungo e tortuoso cammino che porta alla conoscenza.

Laying the path to consumer-level immersive simulation environment

Since the end of the long winter of virtual reality (VR) at the beginning of the 2010 decade, many improvements have been made in terms of hardware technologies and software platforms performances and costs. Many expect such trend will continue, pushing the penetration rate of virtual reality headsets to skyrocket at some point in the future, just as mobile platforms did before. In the meantime, virtual reality is slowly transitioning from a specialized laboratory-only technology, to a consumer electronics appliance, opening interesting opportunities and challenges. In this transition, two interesting research questions amount to how 2D-based content and applications may benefit (or be hurt) by the adoption of 3D-based immersive environments and to how to proficiently support such integration. Acknowledging the relevance of the former, we here consider the latter question, focusing our attention on the diversified family of PC-based simulation tools and platforms. VR-based visualization is, in fact, widely understood and appreciated in the simulation arena, but mainly confined to high performance computing laboratories. Our contribution here aims at characterizing the simulation tools which could benefit from immersive interfaces, along with a general framework and a preliminary implementation which may be put to good use to support their transition from uniquely 2D to blended 2D/3D environments.

Heat kernel and worldline path integrals for the Proca theory

In this thesis we study the heat kernel, a useful tool to analyze various properties of different quantum field theories. In particular, we focus on the study of the one-loop effective action and the application of worldline path integrals to derive perturbatively the heat kernel coefficients for the Proca theory of massive vector fields. It turns out that the worldline path integral method encounters some difficulties if the differential operator of the heat kernel is of non-minimal kind. More precisely, a direct recasting of the differential operator in terms of worldline path integrals, produces in the classical action a non-perturbative vertex and the path integral cannot be solved. In this work we wish to find ways to circumvent this issue and to give a suggestion to solve similar problems in other contexts.