223 research outputs found

    Fault-tolerant feature-based estimation of space debris motion and inertial properties

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    The exponential increase of the needs of people in the modern society and the contextual development of the space technologies have led to a significant use of the lower Earth’s orbits for placing artificial satellites. The current overpopulation of these orbits also increased the interest of the major space agencies in technologies for the removal of at least the biggest spacecraft that have reached their end-life or have failed their mission. One of the key functionalities required in a mission for removing a non-cooperative spacecraft is the assessment of its kinematics and inertial properties. In a few cases, this information can be approximated by ground observations. However, a re-assessment after the rendezvous phase is of critical importance for refining the capture strategies preventing accidents. The CADET program (CApture and DE-orbiting Technologies), funded by Regione Piemonte and led by Aviospace s.r.l., involved Politecnico di Torino in the research for solutions to the above issue. This dissertation proposes methods and algorithms for estimating the location of the center of mass, the angular rate, and the moments of inertia of a passive object. These methods require that the chaser spacecraft be capable of tracking several features of the target through passive vision sensors. Because of harsh lighting conditions in the space environment, feature-based methods should tolerate temporary failures in detecting features. The principal works on this topic do not consider this important aspect, making it a characteristic trait of the proposed methods. Compared to typical v treatments of the estimation problem, the proposed techniques do not depend solely on state observers. However, methods for recovering missing information, like compressive sampling techniques, are used for preprocessing input data to support the efficient usage of state observers. Simulation results showed accuracy properties that are comparable to those of the best-known methods already proposed in the literature. The developed algorithms were tested in the laboratory staged by Aviospace s.r.l., whose name is CADETLab. The results of the experimental tests suggested the practical applicability of such algorithms for supporting a real active removal mission

    High concentration photovoltaic system with parallel kinematic solar tracker

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    The paper introduces a high concentration photovoltaic system developed at Politecnico di Torino. The system includes a new kind of solar tracker, based on a parallel kinematic mechanism, some high concentration photovoltaic modules and a heat recovery circuit intended for recovering heat from the chilling plant. The paper in its first part describes in deep the design of the tracker and the control strategy used to drive it. In the second part the construction of a 2,8 kWp prototype is described and some results about experimental tests are show

    Free will, neuroscience, and choice: towards a decisional capacity model for insanity defense evaluations

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    Il libero arbitrio è stato spesso considerato una tematica centrale nella dottrina della responsabilità criminale. Ciononostante, il concetto stesso di libero arbitrio presenta intrinseche problematiche nella sua definizione teorica e applicazione pratica in un contesto clinico/ forense ed è intensamente dibattuto. Nello specifico, l’esistenza stessa del libero arbitrio è stata recentemente posta in discussione anche sulla base di alcune evidenze sperimentali neuroscientifiche. Questo dibattito ha implicazioni significative in quei campi in cui l’associazione tra libertà di scelta è comportamento costituisce il focus di interesse, quali la psichiatria forense. Esiste inoltre una sorta di conflittualità tra la centralità e concezione teorica del libero arbitrio (free will) e il suo status e applicazione pratica. Questo problema ha bisogno di essere affrontato, specialmente all’interno della psichiatria forense, dal momento che risulta rilevante per l’effettiva valutazione dell’infermità di mente. Nel presente articolo cercheremo di rendere operativo il concetto del “libero arbitrio” utilizzando il modello a quattro dimensioni utilizzato per la capacità decisionale, che può essere impiegato nella valutazione forense dell’infermità di mente. Descriveremo i suoi vantaggi e applicazioni per guidare la valutazione dell’infermità di mente. Mentre il libero arbitrio è spesso considerato problematico dal punto di vista delle neuroscienze, questo modello, a nostro avviso, è compatibile con le neuroscienze; inoltre, le valutazioni che utilizzino questo modello possono anche essere arricchite e rafforzate dalle scoperte neuro scientifiche, per esempio riguardo il controllo inibitorioFree will has often been considered central to criminal responsibility. Yet, the concept of free will is also difficult to define and operationalize, and, moreover, it is intensely debated. In particular, the very existence of free will has been denied based on recent neuroscience findings. This debate has significant implications on those fields in which the link between free will and behaviour is the main focus of interest, such as forensic psychiatry. In fact, a tension is often experienced between the centrality of the notion of free will on the one hand, and its controversial status on the other. This tension needs to be addressed, especially in forensic psychiatry, since it is relevant for actual assessments of legal insanity. In the present paper we will try to operationalize “free will” using a fourpartite decision-making capacity model, which can be used in forensic assessment of insanity. We will describe its advantages and application to guide mental insanity assessments. Whereas free will is often considered problematic from a neuroscience perspective, this model, we argue, is compatible with neuroscience; moreover, evaluations using this model can also be informed and strengthened by neuroscientific findings, for example regarding inhibitory control

    The admission experience survey italian version (I-AES). a factor analytic study on a sample of 156 acute psychiatric in-patients

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    Coercive treatments are often regarded as an inevitable and yet highly debated feature of psychiatric care. Perceived coercion is often reported by patients involuntarily committed as well as their voluntary counterparts. The Admission Experience Survey (AES) is a reliable tool for measuring perceived coercion in mental hospital admission. We developed the Italian AES (I-AES) through translation back-translation and administered it to 156 acutely hospitalized patients (48% women, 69% voluntarily committed) in two university hospitals in Rome (Policlinico Umberto I, Sant'Andrea Hospital). A principal component analysis (PCA) with equamax rotation was conducted. The I-AES showed good internal consistency (Cronbach's alpha = 0.90); Guttmann split-half relia- bility coefficient was 0.90. AES total score significantly differed between voluntary and involuntary committed patients (5.08 ± 4.1 vs. 8.1 ± 4.9, p < .05). PCA disclosed a three-factor solution explaining 59.3 of the variance. Some discrepancies were found between the factor structure of the I-AES and the original version. I- AES total score was positively associated with numbers of previous involuntarily hospitalization (r = 0.20, p < .05) and psychiatric symptoms' severity (r = 0.22, p < .02). I-AES and its proposed new factor structure proved to be reliable to assess perceived coercion in mental hospital admission. Consequently, it may represent a helpful instrument for the study and reduction of patients' levels of perceived coercion

    Scheduling Replica Voting in Fixed-Priority Real-Time Systems

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    Reliability and safety are mandatory requirements for safety-critical embedded systems. The design of a fault-tolerant system is required in many fields (e.g., railway, automotive, avionics) and redundancy helps in achieving this goal. Redundant systems typically leverage voting techniques applied to the outputs produced by tasks to detect and even tolerate failures. This paper studies the integration of distributed voting protocols in fixed-priority real-time systems from a scheduling perspective. It analyzes two scheduling strategies for implementing voting. One is attractive and friendly for software developers and based on suspending the task execution until the replica provides the data to be voted. The other one is inspired by the Logical Execution Time (LET) paradigm and requires introducing additional tasks in the system to accomplish voting-related activities. Queuing and delays introduced by inter-replica communication interfaces are also analyzed. Experimental results are finally presented to compare the two strategies, showing that LET-inspired voting is much more predictable and hence more suitable than the other strategy for fixed-priority real-time systems

    What every psychiatrist should know about PANDAS: a review

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    The term Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcus infections (PANDAS) was coined by Swedo et al. in 1998 to describe a subset of childhood obsessive-compulsive disorders (OCD) and tic disorders triggered by group-A beta-hemolytic Streptococcus pyogenes infection. Like adult OCD, PANDAS is associated with basal ganglia dysfunction. Other putative pathogenetic mechanisms of PANDAS include molecular mimicry and autoimmune-mediated altered neuronal signaling, involving calcium-calmodulin dependent protein (CaM) kinase II activity. Nonetheless the contrasting results from numerous studies provide no consensus on whether PANDAS should be considered as a specific nosological entity or simply a useful research framework. Herein we discuss available data that could provide insight into pathophysiology of adult OCD, or might explain cases of treatment-resistance. We also review the latest research findings on diagnostic and treatment

    A Holographic Diffuser Generalised Optical Differentiation Wavefront Sensor

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    The wavefront sensors used today at the biggest World's telescopes have either a high dynamic range or a high sensitivity, and they are subject to a linear trade off between these two parameters. A new class of wavefront sensors, the Generalised Optical Differentiation Wavefront Sensors, has been devised, in a way not to undergo this linear trade off and to decouple the dynamic range from the sensitivity. This new class of WFSs is based on the light filtering in the focal plane from a dedicated amplitude filter, which is a hybrid between a linear filter, whose physical dimension is related to the dynamic range, and a step in the amplitude, whose size is related to the sensitivity. We propose here a possible technical implementation of this kind of WFS, making use of a simple holographic diffuser to diffract part of the light in a ring shape around the pin of a pyramid wavefront sensor. In this way, the undiffracted light reaches the pin of the pyramid, contributing to the high sensitivity regime of the WFS, while the diffused light is giving a sort of static modulation of the pyramid, allowing to have some signal even in high turbulence conditions. The holographic diffuser zeroth order efficiency is strictly related to the sensitivity of the WFS, while the diffusing angle of the diffracted light gives the amount of modulation and thus the dynamic range. By properly choosing these two parameters it is possible to build a WFS with high sensitivity and high dynamic range in a static fashion. Introducing dynamic parts in the setup allows to have a set of different diffuser that can be alternated in front of the pyramid, if the change in the seeing conditions requires it.Comment: 11 pages, 5 figure

    Cardiac surgery in the time of the novel coronavirus:Why we should think to a new normal

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    On 11 March 2020, the World Health Organization declared the SARS-CoV-2 outbreak a pandemic. At the time of writing, 24 May 2020 more than 5 million individuals have been tested positive and the death toll was over 330 000 deaths worldwide. The initial data pointed out the tight bond between cardiovascular diseases and worse health outcomes in COVID19-patients. Epidemiologically speaking, there is an overlap between the age-groups more affected by COVID-related death and the age-groups in which Cardiac Surgery has its usual base of patients. The Cardiac Surgery Departments have to think to anew normal: since the virus will remain endemic in the society, dedicated pathways or even dedicated Teams are pivotal to treat safely the patients, in respect of the safety of the health care workers. Moreover, we need a keen eye on deciding which pathologies have to be treated with priority: Coronary artery Disease showed a higher mortality rate in patients affected by COVID19, but it is, however, reasonable to think that all the cardiac pathologies affecting the lung circulation-such as symptomatic severe mitral diseases or aortic stenosis-might deserve a priority access to treatment, to increase the survival rate in case of an acquired-Coronavirus infection later on

    Health related quality of life in colorectal cancer patients: state of the art

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    Proceedings of the 26th National Congress of the Italian Society of Geriatric Surgery Silvestro Canonico, Bruno Amato and Alessandro Puzziello This supplement has not been sponsored. The source of funding used to cover open access publication charges is declared by the authors in each article. Articles have undergone the journal's standard review process for supplements. The supplement editors declare they have no competing interests. Conference 26th National Congress of the Italian Society of Geriatric Surgery 19-22 June 2013 Naples, ItalyBACKGROUND: Colorectal cancer (CRC) is the third most commonly diagnosed cancer in males and the second in females with a progressive increase in prevalence in industrialized countries. The loss of health due to the cancer and/or the consequence of the treatment may result in psychophysical, functional and social impairment; all of these affect health-related quality of life (QoL). DESCRIPTION: The most frequently CRC-specific QoL questionnaires is the FACT-C. QoL is not only important for the well-being of cancer patient but it also influences survival and response to therapy. Many studies investigated various determinants involved in the assessment of QoL in CRC, suggesting that symptoms, surgical procedures and the number of comorbidity significantly affected QoL. CONCLUSION: Despite that CRC patients have a relatively good QoL compared with the general population, a wide range of intervention could be undertaken to improve their QoL. The finding of this review may be useful for cancer clinicians in taking therapy and surveillance-related decisions. However, future research should be directed to large-scale prospective studies using well validated QoL instruments to facilitate comparison of results.Funding for this article has come from University funds.S
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