Spherical clustering of users navigating 360{\deg} content

In Virtual Reality (VR) applications, understanding how users explore the omnidirectional content is important to optimize content creation, to develop user-centric services, or even to detect disorders in medical applications. Clustering users based on their common navigation patterns is a first direction to understand users behaviour. However, classical clustering techniques fail in identifying these common paths, since they are usually focused on minimizing a simple distance metric. In this paper, we argue that minimizing the distance metric does not necessarily guarantee to identify users that experience similar navigation path in the VR domain. Therefore, we propose a graph-based method to identify clusters of users who are attending the same portion of the spherical content over time. The proposed solution takes into account the spherical geometry of the content and aims at clustering users based on the actual overlap of displayed content among users. Our method is tested on real VR user navigation patterns. Results show that our solution leads to clusters in which at least 85% of the content displayed by one user is shared among the other users belonging to the same cluster.Comment: 5 pages, conference (Published in: ICASSP 2019 - 2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

Anàlisi dels resultats i consideracions per l'aplicació a l'assignatura d'habilitats socials i comunicatives

Presentació de resultats de la prova de rúbrica d'avaluació CPA de l'assignatura d'Habilitats Socials i Comunicatives del Grau de Treball Socia

Streaming and User Behaviour in Omnidirectional Videos

Omnidirectional videos (ODVs) have gone beyond the passive paradigm of traditional video, offering higher degrees of immersion and interaction. The revolutionary novelty of this technology is the possibility for users to interact with the surrounding environment, and to feel a sense of engagement and presence in a virtual space. Users are clearly the main driving force of immersive applications and consequentially the services need to be properly tailored to them. In this context, this chapter highlights the importance of the new role of users in ODV streaming applications, and thus the need for understanding their behaviour while navigating within ODVs. A comprehensive overview of the research efforts aimed at advancing ODV streaming systems is also presented. In particular, the state-of-the-art solutions under examination in this chapter are distinguished in terms of system-centric and user-centric streaming approaches: the former approach comes from a quite straightforward extension of well-established solutions for the 2D video pipeline while the latter one takes the benefit of understanding users’ behaviour and enable more personalised ODV streaming

Explaining Hierarchical Features in Dynamic Point Cloud Processing

This paper aims at bringing some light and understanding to the field of deep learning for dynamic point cloud processing. Specifically, we focus on the hierarchical features learning aspect, with the ultimate goal of understanding which features are learned at the different stages of the process and what their meaning is. Last, we bring clarity on how hierarchical components of the network affect the learned features and their importance for a successful learning model. This study is conducted for point cloud prediction tasks, useful for predicting coding applications

Spatio-temporal Graph-RNN for Point Cloud Prediction

In this paper, we propose an end-to-end learning network to predict future frames in a point cloud sequence. As main novelty, an initial layer learns topological information of point clouds as geometric features, to form representative spatio-temporal neighborhoods. This module is followed by multiple Graph-RNN cells. Each cell learns points dynamics (i.e., RNN states) by processing each point jointly with the spatio-temporal neighbouring points. We tested the network performance with a MINST dataset of moving digits, a synthetic human bodies motions and JPEG dynamic bodies datasets. Simulation results demonstrate that our method outperforms baseline ones that neglect geometry features information

Optimal fault-tolerant placement of relay nodes in a mission critical wireless network

The operations of many critical infrastructures (e.g., airports) heavily depend on proper functioning of the radio communication network supporting operations. As a result, such a communication network is indeed a mission-critical communication network that needs adequate protection from external electromagnetic interferences. This is usually done through radiogoniometers. Basically, by using at least three suitably deployed radiogoniometers and a gateway gathering information from them, sources of electromagnetic emissions that are not supposed to be present in the monitored area can be localised. Typically, relay nodes are used to connect radiogoniometers to the gateway. As a result, some degree of fault-tolerance for the network of relay nodes is essential in order to offer a reliable monitoring. On the other hand, deployment of relay nodes is typically quite expensive. As a result, we have two conflicting requirements: minimise costs while guaranteeing a given fault-tolerance. In this paper address the problem of computing a deployment for relay nodes that minimises the relay node network cost while at the same time guaranteeing proper working of the network even when some of the relay nodes (up to a given maximum number) become faulty (fault-tolerance). We show that the above problem can be formulated as a Mixed Integer Linear Programming (MILP) as well as a Pseudo-Boolean Satisfiability (PB-SAT) optimisation problem and present experimental results com- paring the two approaches on realistic scenarios

Extending 3-DoF Metrics to Model User Behaviour Similarity in 6-DoF Immersive Applications

Immersive reality technologies, such as Virtual and Augmented Reality, have ushered a new era of user-centric systems, in which every aspect of the coding--delivery--rendering chain is tailored to the interaction of the users. Understanding the actual interactivity and behaviour of the users is still an open challenge and a key step to enabling such a user-centric system. Our main goal is to extend the applicability of existing behavioural methodologies for studying user navigation in the case of 6 Degree-of-Freedom (DoF). Specifically, we first compare the navigation in 6-DoF with its 3-DoF counterpart highlighting the main differences and novelties. Then, we define new metrics aimed at better modelling behavioural similarities between users in a 6-DoF system. We validate and test our solutions on real navigation paths of users interacting with dynamic volumetric media in 6-DoF Virtual Reality conditions. Our results show that metrics that consider both user position and viewing direction better perform in detecting user similarity while navigating in a 6-DoF system. Having easy-to-use but robust metrics that underpin multiple tools and answer the question ``how do we detect if two users look at the same content?" open the gate to new solutions for a user-centric system

Extending 3-DoF Metrics to Model User Behaviour Similarity in 6-DoF Immersive Applications

Immersive reality technologies, such as Virtual and Augmented Reality, have ushered a new era of user-centric systems, in which every aspect of the coding-delivery-rendering chain is tailored to the interaction of the users. Understanding the actual interactivity and behaviour of the users is still an open challenge and a key step to enabling such a user-centric system. Our main goal is to extend the applicability of existing behavioural methodologies for studying user navigation in the case of 6 Degree-of-Freedom (DoF). Specifically, we first compare the navigation in 6-DoF with its 3-DoF counterpart highlighting the main differences and novelties. Then, we define new metrics aimed at better modelling behavioural similarities between users in a 6-DoF system. We validate and test our solutions on real navigation paths of users interacting with dynamic volumetric media in 6-DoF Virtual Reality conditions. Our results show that metrics that consider both user position and viewing direction better perform in detecting user similarity while navigating in a 6-DoF system. Having easy-to-use but robust metrics that underpin multiple tools and answer the question "how do we detect if two users look at the same content?" open the gate to new solutions for a user-centric syste

La qualità della regolazione nell’esperienza della Consob: dalla misurazione degli oneri amministrativi al ciclo della valutazione. Il caso dell’equity crowdfunding

5noLa regolazione è un’attività ciclica, un processo continuo nel quale sussiste un legame intrinseco tra l’individuazione delle problematiche, la definizione, la valutazione e la revisione degli obiettivi e degli strumenti di attuazione delle politiche pubbliche. La Consob, in qualità di Autorità amministrativa indipendente avente funzioni di regolazione e di vigilanza di settore, è tenuta, a partire dal 2003, ad adottare metodologie di Analisi di Impatto della Regolamentazione (AIR) nel disegno dei provvedimenti generali di propria competenza. La previsione relativa all’effettuazione dell’AIR da parte della Consob è stata successivamente rafforzata attraverso l’articolo 23 della legge 28 dicembre 2005 n. 262 “Disposizioni per la tutela del risparmio e la disciplina dei mercati finanziari” che ha introdotto la procedimentalizzazione per l’adozione degli atti regolamentari e generali della Banca d’Italia, della Consob, dell’Isvap (oggi IVASS) e della Covip, stabilendone alcuni principi. La Consob, pertanto, affrontando l’attuazione delle deleghe contenute negli atti legislativi da cui ha origine il proprio potere regolamentare, ha sviluppato un solido patrimonio di conoscenze ed esperienze, maturato nel corso del precedente decennio con riferimento alle migliori metodologie di produzione normativa. Tale patrimonio è stato integrato nel tempo mediante lo studio e l’applicazione di strumenti di Better Regulation condivisi in ambito internazionale ed europeo. L’ipotesi che il presente lavoro contribuisce a sostenere è che l’impiego di tali strumenti nel processo normativo-regolamentare possa contribuire ad ottenere una migliore qualità delle regole. A tale fine, vengono presentati due progetti tra loro strettamente connessi, attraverso i quali è stato possibile sperimentare tali metodi ed elaborare proposte in grado di ridurre l’onerosità e accrescere i benefici della regolamentazione: il “Progetto MOA” concernente la regolamentazione della Consob in materia di emittenti, intermediari e mercati e il “Ciclo di Valutazione ” relativo all’adozione, al monitoraggio e alla successiva revisione del Regolamento Consob in materia di equity crowdfunding..openopenMirra, Vittorio; Zaottini, Davide; Fiamma, Francesca; Carbone, Silvia; Marcelli, ToniMirra, Vittorio; Zaottini, Davide; Fiamma, Francesca; Carbone, Silvia; Marcelli, Ton

Hip subluxation in Italian cerebral palsy children and its determinants: a retrospective cohort study

The study's aim was two-fold: to describe the trend of hip subluxation in the largest sample of Italian nonambulatory cerebral palsy (CP) children ever published; to investigate its determinants. This single-centre retrospective cohort study included patients with spastic or dyskinetic CP, Gross Motor Function Classification System (GMFCS) level IV or V, age 0-18 years, having been referred to our unit before March 2020. The hip subluxation was measured by means of the migration percentage (MP). Other data were gathered such as sex, CP subtype, GMFCS level, presence of drug-resistant epilepsy, age, use of walkers with weight relief or standing devices, previous botulinum injection or hip surgery, oral or intrathecal baclofen and hip pain. Multiple linear stepwise regression was performed and descriptive statistics are provided. Spastic CP had MP maximum increase in early ages, with GMFCS level V values persistently higher than level IV. The dyskinetic subtype showed a slower increase of the MP, with GMFCS level IV presenting similar or higher values, compared to level V. Age, CP severity and spastic subtype are the main determinants. The stepwise multiple regression analysis demonstrated that weight relief walking and standing assistive devices, combined with botulinum contributed to reduce the MP progression. Dyskinetic CP showed overall lower MP values and a more variable behaviour relative to age and GMFCS level, compared to the spastic subtype. Standing and walking assistive devices, with partial or total weight relief, combined with individually targeted botulinum injections, should be considered in the management of bilateral nonambulatory CP patients, to prevent hip subluxation or its recurrence after surgery