An Architecture for Observational Learning

In this thesis I present an architecture that learns new skills through observation and adapts to the environment through situated experience in the world. Such an architectural growth is bootstrapped from a minimal initial knowledge and the architecture itself is built around the biologically-inspired notion of internal models. The key idea, supported by findings in cognitive neuroscience, is that the same internal models used in overt goal-directed action execution can be covertly re-enacted in simulation to observe and understand the actions of others. The system applies these concepts to learning higher order cognitive functions like learning problem solving skills and social interaction skills. Rather than rea- soning over abstract symbols, the system relies on biologically plausible processes firmly grounded in the actual sensori-motor experience of the agent. The system continuously learns new models and revises existing ones through the observation of other intentional agents in the world and through direct indivi- dual experience. The learning process accumulates knowledge about causal rela- tions between observed events, and acquires complex skills observing and abstract- ing the goals of a demonstrator. To reach its goals, the system exploits the acquired knowledge and uses its internal models to reason about future consequences of its actions. The architec- ture anticipates future needs and perils and through its internal models used in simulation it reasons about the future in a way detached from the current situation. This thesis presents also two case studies used to test the ideas constituting the architecture. The first is a classical AI problem-solving domain: the Sokoban puzzle; the second is the domain of social interaction

Assessment of cerebral microbleeds by susceptibility-weighted imaging in Alzheimer's disease patients: A neuroimaging biomarker of the disease

Purpose The objective of this study was to correlate the presence and distribution of cerebral microbleeds in Alzheimer's disease patients with cerebrospinal fluid biomarkers (amyloid-beta and phosphorylated tau 181 protein levels) and cognitive decline by using susceptibility-weighted imaging magnetic resonance sequences at 1.5 T. Material and methods Fifty-four consecutive Alzheimer's disease patients underwent brain magnetic resonance imaging at 1.5 T to assess the presence and distribution of cerebral microbleeds on susceptibility-weighted imaging images. The images were analyzed in consensus by two neuroradiologists, each with at least 10 years' experience. Dementia severity was assessed with the Mini-Mental State Examination score. A multiple regression analysis was performed to assess the associations between the number and location of cerebral microbleed lesions with the age, sex, duration of the disease, cerebrospinal fluid amyloid-beta and phosphorylated tau 181 protein levels, and cognitive functions. Results A total of 296 microbleeds were observed in 54 patients; 38 patients (70.4%) had lobar distribution, 13 patients (24.1%) had non-lobar distribution, and the remaining three patients (5.6%) had mixed distribution, demonstrating that Alzheimer's disease patients present mainly a lobar distribution of cerebral microbleeds. The age and the duration of the disease were correlated with the number of lobar cerebral microbleeds (P < 0.001). Cerebrospinal fluid amyloid-beta, phosphorylated tau 181 protein levels, and cognitive decline were correlated with the number of lobar cerebral microbleeds in Alzheimer's disease patients (P < 0.001). Conclusion Lobar distribution of cerebral microbleeds is associated with Alzheimer's disease and the number of lobar cerebral microbleeds directly correlates with cerebrospinal fluid amyloid-beta and phosphorylated tau 181 protein levels and with the cognitive decline of Alzheimer's disease patients

Encefalopatia ipertensiva cronica (EIC): sensibilita\u300 delle sequenze GE-T2* a confronto con le SWI nell'identificazione dei micro-sanguinamenti

L'EIC e\u300 caratterizzata dalla presenza di lesioni parenchimali irreversibili, risultato di una lunga esposizione a regimi pressori patologici specie in pazienti che non seguono o non rispondono alle comuni terapie mediche. Si riscontrano quali reperti tipici multipli esiti gliotici, leucoaraiosi e multiple lesioni lacunari con predilezione per le localizzazioni profonde ai nuclei lenticolari, ai talami e al ponte. Piu\u300 raramente possono evidenziarsi minuti foci emorragici parenchimali, piu\u300 frequentemente localizzati nei gangli della base ma anche nel ponte e nel cervelletto, che in alcuni casi possono rappresentare la manifestazione principale della patologia: questi microsanguinamenti, visibili incostantemente in TC, sono classicamente ben individuabili in RM come aree di netta ipointensita\u300 di segnale in GRE (Gradient Recalled Echo) T2* pesate. Scopo del nostro lavoro e\u300 quello di presentare due casi in cui l'EIC si manifesta prevalentemente con un quadro micro-emorragico confrontando la sensibilita\u300 delle convenzionali sequenze GRE T2* pesate con sequenze sensibili al fenomeno della suscettivita\u300 magnetica (Susceptibility-Weighted Imaging, SWI) di piu\u300 recente introduzione nella routine diagnostica

Four cases of progressive multifocal leukoencephalopathy in iatrogenic immunocompromised patients

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system (CNS) caused by John Cunningham Virus (JCV). We report four PML cases in immunocompromised patients, respectively treated with (1) Natalizumab, (2) Rituximab, (3) autologous stem-cell transplantation, and (4) Tacrolimus. All patients underwent neurological examination, magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), JCV-DNA research on biological samples, and lymphocytes subpopulation study. All cases presented with motor, behavioural, and cognitive disorders. Visual, sensitive, and cerebellar deficits developed in three cases. MRI revealed widespread progressive demyelinating areas with active borders; three patients presented contrast enhancement. One patient developed inflammatory reconstitution syndrome (IRIS). At MRS, all cases presented decreased N-acetyl-aspartate (NAA) and three cases showed increased choline (Cho). In one patient, plasma and urine tested positive for JCV-DNA, while cerebrospinal fluid (CSF) analysis confirmed JCV in two patients. The fourth patient had a low JCV-DNA blood titer and brain biopsy showed subacute necrosis. Two patients had abnormal lymphocyte subpopulations. Three patients underwent therapy with Mirtazapine, one of whom received Mefloquine in add-on. No clinical response was registered. Clinical onset, MRI and MRS were highly suggestive of PML in all patients, despite three cases presented contrast enhancement. In three cases JCV-DNA detection in biological samples confirmed the diagnosis. The fourth patient fulfilled diagnosis of “presumptive PML”. Our data confirm the importance to complete the diagnostic workup despite the presence of findings not completely consistent with classical PML. We hypothesize that atypical characteristics could due to the clinical conditions leading to PML

Risultato di valorizzazione applicativa: progettazione e realizzazione di un prototipo di sensore wireless per il monitoraggio di carichi elettrici in ambiente Smart Building

Oggetto del presente lavoro è stata la progettazione e realizzazione di un prototipo di sensore wireless a basso costo per il monitoraggio di carichi elettrici in ambiente Smart Building, capace di inviare dati ad un sistema remoto (ad esempio un EMS) mediante una comune connessione WiFi. L’attività si inquadra nell’ambito di una collaborazione scientifica tra l’Istituto di Studi sui Sistemi Intelligenti per l’Automazione (ISSIA) del Consiglio Nazionale delle Ricerche (CNR) e il Dipartimento di Matematica e Informatica (DMI) dell’Università degli Studi di Palermo (UNIPA). Il prototipo è stato realizzato interfacciando opportunamente alcuni dispositivi hardware commerciali, aggiungendo gli opportuni circuiti per il condizionamento dei segnali da acquisire e scrivendo il codice per l’implementazione del firmware del sensore wireless (per l’invio dei dati) e del client remoto (per la ricezione dei dati)

Examining bi-directionality between Fear of Missing Out and problematic smartphone use. A two-wave panel study among adolescents

Background: In recent years, the Fear of Missing Out (FoMO) construct has been the object of growing attention in digital technology research with previous studies finding support for the relationship between FoMO and problematic smartphone use (PSU) among adolescents and young adults. However, no previous studies clarified the causal link between FoMO and PSU using a longitudinal design. Methods: An auto-regressive, cross-lagged panel design was tested by using a longitudinal dataset with two waves of data collection (T0 and T1, one year apart). Participants included two hundred and forty-two adolescents (109 males and 133 females), with a mean age of 14.16 years, who filled out the Fear of Missing Out scale (FoMOs) and the Smartphone Addiction Scale (SAS). Moreover, participants filled out the Difficulties in Emotion Regulation Scale (DERS), at the first time-point of data collection. Results: The findings of the study show that FoMO (both FoMO-Fear and FoMO-Control subscales) and PSU are positively related at both time-points (i.e. at a cross-sectional level). However no cross-lagged associations between them were longitudinally supported. Females and older adolescents show higher FoMO-Fear at T1. Conclusions: The findings of the present study suggest caution when causal links between FoMO and PSU are inferred

Modeling and performance assessment of the split-pi used as a storage converter in all the possible dc microgrid scenarios. Part i: Theoretical analysis

The integration of an electrical storage system (ESS) into a DC microgrid using a bidirectional DC/DC converter provides substantial benefits but requires careful design. Among such converter topologies, the Split-pi converter presents several merits at the cost of non-isolated operation. However, the few works in the literature on the Split-pi presented only closed-loop control with a single control loop; furthermore, they neglected the reactive components’ parasitic resistances and did not perform any experimental validation. This work aimed at investigating the use of the Split-pi converter as a power interface between an ESS and a DC microgrid. Five typical microgrid scenarios are presented, where each of which requires a specific state-space model and a suitable control scheme for the converter to obtain high performance. In this study, two different state-space models of the converter that consider the parasitic elements are presented, the control schemes are discussed, and criteria for designing the controllers are also given. Several simulations, as well as experimental tests on a prototype realized in the lab, were performed to validate the study. Both the simulation and experimental results will be presented in part II of this work. The proposed approach has general validity and can also be followed when other bidirectional DC/DC converter topologies are employed to interface an ESS with a DC microgrid

Malignancy course of pituitary adenoma in MEN1 syndrome: Clinical-Neuroradiological signs

Pituitary carcinomas (PCa) are extremely rare, indistinguishable from pituitary adenomas on histopathological grounds and have a poor prognosis. Most PCa start as PRL or ACTH secreting tumors in males, with relapsing invasive behaviour, refractoriness to medical and radiotherapy and increasing hormonal levels. The presence of distant metastases is still required for the diagnosis of PCa. The association with genetic endocrine diseases must be taken into account, since it adds further risk of evolution towards malignancy. Intradural spinal metastases have also been reported, so a complete craniospinal MR evaluation is recommended, when clinically indicated. We report a case of PCa, associated with MEN1 syndrome, with evidence of meningeal spread to the tentorium cerebelli, clival dura and spinal drop metastases mimicking spinal nerves schwannomas

Modeling and Experimental Validation of a Voltage-Controlled Split-Pi Converter Interfacing a High-Voltage ESS with a DC Microgrid

The Split-pi converter can suitably interface an energy storage system (ESS) with a DC microgrid when galvanic isolation is not needed. Usually, the ESS voltage is lower than the grid-side voltage. However, limitations in terms of the ESS current make the use of a high-voltage ESS unavoidable when high power levels are required. In such cases, the ESS voltage can be higher than the microgrid voltage, especially with low microgrid voltages such as 48 V. Despite its bidirectionality and symmetry, the Split-pi exhibits a completely different dynamic behavior if its input and output ports are exchanged. Thus, the present work aims to model the Split-pi converter operating with an ESS voltage higher than the grid-side voltage in three typical microgrid scenarios where the controlled variable is the converter's output voltage. The devised state-space model considers the parasitic elements and the correct load model for each scenario. Furthermore, it is shown that the presence of the input LC filter can make the design of the loop controllers more complicated than in the case of a lower ESS voltage than the grid-side voltage. Finally, the study is validated through simulations and experimental tests on a lab prototype, and a robustness analysis is performed

Modeling and performance assessment of the split-pi used as a storage converter in all the possible dc microgrid scenarios. Part II: Simulation and experimental results

Bidirectional DC/DC converters such as the Split-pi can be used to integrate an energy storage system (ESS) into a DC microgrid providing manifold benefits. However, this integration deserves careful design because the ESS converter must behave like a stiff voltage generator, a non-stiff voltage generator, or a current generator depending on the microgrid configuration. Part I of this work presented a comprehensive theoretical analysis of the Split-pi used as an ESS converter in all the possible DC microgrid scenarios. Five typical microgrid scenarios were identified. Each of them required a specific state-space model of the Split-pi and a suitable control scheme. The present paper completes the study validating the theoretical analysis based on simulations and experimental tests. The chosen case study encompassed a 48 V, 750 W storage system interfaced with a 180 V DC microgrid using a Split-pi converter. It can represent a reduced-power prototype of terrestrial and marine microgrids. A prototypal Split-pi converter was realized in the lab, and several experimental tests were performed to assess the performance in each scenario. The results obtained from the experimental tests were coherent with the simulations and validated the study