Global Propagation of Singularities for Time Dependent Hamilton-Jacobi Equations

We investigate the properties of the set of singularities of semiconcave solutions of Hamilton-Jacobi equations of the form \begin{equation*} u_t(t,x)+H(\nabla u(t,x))=0, \qquad\text{a.e. }(t,x)\in (0,+\infty)\times\Omega\subset\mathbb{R}^{n+1}\,. \end{equation*} It is well known that the singularities of such solutions propagate locally along generalized characteristics. Special generalized characteristics, satisfying an energy condition, can be constructed, under some assumptions on the structure of the Hamiltonian $H$. In this paper, we provide estimates of the dissipative behavior of the energy along such curves. As an application, we prove that the singularities of any viscosity solution of the above equation cannot vanish in a finite time

Shared Perception in Human-Robot Interaction

Interaction can be seen as a composition of perspectives: the integration of perceptions, intentions, and actions on the environment two or more agents share. For an interaction to be effective, each agent must be prone to “sharedness”: being situated in a common environment, able to read what others express about their perspective, and ready to adjust one’s own perspective accordingly. In this sense, effective interaction is supported by perceiving the environment jointly with others, a capability that in this research is called Shared Perception. Nonetheless, perception is a complex process that brings the observer receiving sensory inputs from the external world and interpreting them based on its own, previous experiences, predictions, and intentions. In addition, social interaction itself contributes to shaping what is perceived: others’ attention, perspective, actions, and internal states may also be incorporated into perception. Thus, Shared perception reflects the observer's ability to integrate these three sources of information: the environment, the self, and other agents. If Shared Perception is essential among humans, it is equally crucial for interaction with robots, which need social and cognitive abilities to interact with humans naturally and successfully. This research deals with Shared Perception within the context of Social Human-Robot Interaction (HRI) and involves an interdisciplinary approach. The two general axes of the thesis are the investigation of human perception while interacting with robots and the modeling of robot’s perception while interacting with humans. Such two directions are outlined through three specific Research Objectives, whose achievements represent the contribution of this work. i) The formulation of a theoretical framework of Shared Perception in HRI valid for interpreting and developing different socio-perceptual mechanisms and abilities. ii) The investigation of Shared Perception in humans focusing on the perceptual mechanism of Context Dependency, and therefore exploring how social interaction affects the use of previous experience in human spatial perception. iii) The implementation of a deep-learning model for Addressee Estimation to foster robots’ socio-perceptual skills through the awareness of others’ behavior, as suggested in the Shared Perception framework. To achieve the first Research Objective, several human socio-perceptual mechanisms are presented and interpreted in a unified account. This exposition parallels mechanisms elicited by interaction with humans and humanoid robots and aims to build a framework valid to investigate human perception in the context of HRI. Based on the thought of D. Davidson and conceived as the integration of information coming from the environment, the self, and other agents, the idea of "triangulation" expresses the critical dynamics of Shared Perception. Also, it is proposed as the functional structure to support the implementation of socio-perceptual skills in robots. This general framework serves as a reference to fulfill the other two Research Objectives, which explore specific aspects of Shared Perception. For what concerns the second Research Objective, the human perceptual mechanism of Context Dependency is investigated, for the first time, within social interaction. Human perception is based on unconscious inference, where sensory inputs integrate with prior information. This phenomenon helps in facing the uncertainty of the external world with predictions built upon previous experience. To investigate the effect of social interaction on such a mechanism, the iCub robot has been used as an experimental tool to create an interactive scenario with a controlled setting. A user study based on psychophysical methods, Bayesian modeling, and a neural network analysis of human results demonstrated that social interaction influenced Context Dependency so that when interacting with a social agent, humans rely less on their internal models and more on external stimuli. Such results are framed in Shared Perception and contribute to revealing the integration dynamics of the three sources of Shared Perception. The others’ presence and social behavior (other agents) affect the balance between sensory inputs (environment) and personal history (self) in favor of the information shared with others, that is, the environment. The third Research Objective consists of tackling the Addressee Estimation problem, i.e., understanding to whom a speaker is talking, to improve the iCub social behavior in multi-party interactions. Addressee Estimation can be considered a Shared Perception ability because it is achieved by using sensory information from the environment, internal representations of the agents’ position, and, more importantly, the understanding of others’ behavior. An architecture for Addressee Estimation is thus designed considering the integration process of Shared Perception (environment, self, other agents) and partially implemented with respect to the third element: the awareness of others’ behavior. To achieve this, a hybrid deep-learning (CNN+LSTM) model is developed to estimate the speaker-robot relative placement of the addressee based on the non-verbal behavior of the speaker. Addressee Estimation abilities based on Shared Perception dynamics are aimed at improving multi-party HRI. Making robots aware of other agents’ behavior towards the environment is the first crucial step for incorporating such information into the robot’s perception and modeling Shared Perception

Shared perception is different from individual perception: a new look on context dependency

Human perception is based on unconscious inference, where sensory input integrates with prior information. This phenomenon, known as context dependency, helps in facing the uncertainty of the external world with predictions built upon previous experience. On the other hand, human perceptual processes are inherently shaped by social interactions. However, how the mechanisms of context dependency are affected is to date unknown. If using previous experience - priors - is beneficial in individual settings, it could represent a problem in social scenarios where other agents might not have the same priors, causing a perceptual misalignment on the shared environment. The present study addresses this question. We studied context dependency in an interactive setting with a humanoid robot iCub that acted as a stimuli demonstrator. Participants reproduced the lengths shown by the robot in two conditions: one with iCub behaving socially and another with iCub acting as a mechanical arm. The different behavior of the robot significantly affected the use of prior in perception. Moreover, the social robot positively impacted perceptual performances by enhancing accuracy and reducing participants overall perceptual errors. Finally, the observed phenomenon has been modelled following a Bayesian approach to deepen and explore a new concept of shared perception.Comment: 14 pages, 9 figures, 1 table. IEEE Transactions on Cognitive and Developmental Systems, 202

Rapporto tecnico sul metodo di produzione di un contenitore “porta otoliti” in resina epossidica a partire da un modello commerciale

Nell'ambito delle attività del Programma Nazionale di raccolta Dati Alieutici, per la raccolta dei dati primari di tipo biologico, tecnico ambientale e socio economico nel settore della pesca, l’IAMC - CNR UOS di Mazara del Vallo e Capo Granitola partecipano a dare attuazione al Programma Nazionale attraverso la raccolta ed analisi di campioni biologici provenienti da catture commerciali (ex modulo Campbiol) e da survey scientifici a mare (MEDITS e MEDIAS). A tal fine, tra l'altro, ogni anno si rende necessario il reperimento di un gran numero di particolari vaschette per la conservazione di otoliti di specie ittiche quali Engraulis encrasicolus e Sardina pilchardus, specie di particolare interesse economico in Mediterraneo e i cui stock vengono annualmente monitorati dal CNR. Si è cercato in prima battuta di acquistare i contenitori “porta otoliti” in questione, ma gli stessi non sono stati trovati in commercio. E’ stato quindi necessario avviare una produzione propria dell’articolo partendo da un modello/esemplare in nostro possesso, cercando con le opportune accortezze di realizzare un clone sia dal punto di vista morfometrico che da quello chimico/meccanico per scongiurare problemi di deformazioni nel tempo che potrebbero causare la perdita dei campioni raccolti

To Whom are You Talking? A Deep Learning Model to Endow Social Robots with Addressee Estimation Skills

Communicating shapes our social word. For a robot to be considered social and being consequently integrated in our social environment it is fundamental to understand some of the dynamics that rule human-human communication. In this work, we tackle the problem of Addressee Estimation, the ability to understand an utterance's addressee, by interpreting and exploiting non-verbal bodily cues from the speaker. We do so by implementing an hybrid deep learning model composed of convolutional layers and LSTM cells taking as input images portraying the face of the speaker and 2D vectors of the speaker's body posture. Our implementation choices were guided by the aim to develop a model that could be deployed on social robots and be efficient in ecological scenarios. We demonstrate that our model is able to solve the Addressee Estimation problem in terms of addressee localisation in space, from a robot ego-centric point of view.Comment: Accepted version of a paper published at 2023 International Joint Conference on Neural Networks (IJCNN). Please find the published version and info to cite the paper at https://doi.org/10.1109/IJCNN54540.2023.10191452 . 10 pages, 8 Figures, 3 Table

Natural Circulation and Integrated Layout Pressurized Water Reactor

A natural circulation and integrated layout PWR is here proposed by a preliminary feasibility study. Its main features are: low unit power and core power density, the same temperatures and pressures of current PWRs, no fuel melting scenario, passive protection systems, pressure suppression containment, long fuel cycle duration and no boron in the primary water. The power station can be designed for electrical power production (700 MWth - 225 MWe), or for combined electricity and heat production (200 MWth); this last solution seems viable even for urban siting. Here only the 225 MWe plant is described. The reactor startup is obtained by heating with a constant and low neutronic power, and a possible procedure is indicated and analyzed. The ATWS of a steam line break accident in hot standby conditions is studied by a suitable calculation program and the results are positive

A smart wearable sensor system for counter-fighting overweight in teenagers

PEGASO is a FP7-funded project whose goal is to develop an ICT and mobile-based platform together with an appropriate strategy to tackle the diffusion of obesity and other lifestyle-related illnesses among teenagers. Indeed, the design of an engaging strategy, leveraging a complementary set of technologies, is the approach proposed by the project to promote the adoption of healthy habits such as active lifestyle and balanced nutrition and to effectively counter-fight the emergence of overweight and obesity in the younger population. A technological key element of such a strategy sees the adoption of wearable sensors to monitor teenagersâ\u80\u99 activities, which is at the basis of developing awareness about the current lifestyle. This paper describes the experience carried out in the framework of the PEGASO project in developing and evaluating wearable monitoring systems addressed to adolescents. The paper describes the methodological approach based on the co-designing of such a wearable system and the main results that, in the first phase, involved a total of 407 adolescents across Europe in a series of focus groups conducted in three countries for the requirements definition phase. Moreover, it describes an evaluation process of signal reliability during the usage of the wearable system. The main results described here are: (a) a prototype of the standardized experimental protocol that has been developed and applied to test signal reliability in smart garments; (b) the requirements definition methodology through a co-design activity and approach to address user requirements and preferences and not only technological specifications. Such co-design approach is able to support a higher system acceptance and usability together with a sustained adoption of the solution with respect to the traditional technology push system development strategy

Behavioral and clinical characteristics of people receiving medical care for HIV infection in an outpatient facility in Sicily, Italy

Aim: The authors examined a cohort of HIV-positive outpatients at the AIDS Center of Palermo University in Italy in order to identify factors related to the frequency of their visits to the outpatient facility for health care services. Methods: Two hundred and twenty-four HIV-infected subjects were enrolled in the study. Demographic and HIV disease characteristics were recorded and assessed with the number of days accessed to our outpatients unit in univariate and multivariate analyses. The potential relationship with immunological status was also analyzed stratifying the patients into groups according to their CD4+ T-cell counts ( 65500 vs, \u2c2500/mm3, and 65200 vs < 200/mm3). Results: Both univariate and multivariate analyses showed that duration of antiretroviral therapy, \u2c25 years and hypertension were significantly associated with a CD4+ T-cell count of, \u2c2500/mm3, whereas geographic origin (Africa) was associated with a CD4+ T-cell count of, \u2c2200/mm3. Mean number of days the patients sought access to day-care services for laboratory tests was negatively associated with CD4+ T-cell count. Conclusion: Patients with low CD4+ T-cell counts showed higher use of health care services, demonstrating how early HIV diagnosis can help to reduce health care costs. The CD4+ T-cell cut-off of 200 cells emphasizes the importance of identifying and managing HIV infection among hard-to-reach groups like vulnerable migrants. In our sle, the illegal status of immigrants does not influence the management of their HIV/AIDS condition, but the lack of European health card that documents the current antiretroviral status, could interfere with the efforts to eradicate AIDS. A better understanding of the major determinants of HIV treatment costs has led to appropriate large-scale actions, which in turn has increased resources and expanded intervention programs. Further guidance should be offered to hard-to-reach groups in order to improve early AIDS diagnosis, and procedures for identifying and managing these vulnerable subjects should be made available to care commissioners and service providers