6,358 research outputs found
A fast and robust hand-driven 3D mouse
The development of new interaction paradigms requires a natural interaction. This means that people should be able to interact with technology with the same models used to interact with everyday real life, that is through gestures, expressions, voice. Following this idea, in this paper we propose a non intrusive vision based tracking system able to capture hand motion and simple hand gestures. The proposed device allows to use the hand as a "natural" 3D mouse, where the forefinger tip or the palm centre are used to identify a 3D marker and the hand gesture can be used to simulate the mouse buttons. The approach is based on a monoscopic tracking algorithm which is computationally fast and robust against noise and cluttered backgrounds. Two image streams are processed in parallel exploiting multi-core architectures, and their results are combined to obtain a constrained stereoscopic problem. The system has been implemented and thoroughly tested in an experimental environment where the 3D hand mouse has been used to interact with objects in a virtual reality application. We also provide results about the performances of the tracker, which demonstrate precision and robustness of the proposed syste
Automatic Mode Switching in Atrial Fibrillation
Automatic mode switching (AMS) algorithms were designed to prevent tracking of atrial tachyarrhythmias (ATA) or other rapidly occurring signals sensed by atrial channels, thereby reducing the adverse hemodynamic and symptomatic consequences of a rapid ventricular response. The inclusion of an AMS function in most dual chamber pacemaker now provides optimal management of atrial arrhythmias and allows the benefit of atrioventricular synchrony to be extended to a population with existing atrial fibrillation. Appropriate AMS depends on several parameters: a) the programmed parameters; b) the characteristics of the arrhythmia; c) the characteristics of the AMS algorithm. Three qualifying aspects constitute an AMS algorithm: onset, AMS response, and resynchronization. Since AMS programs also provide data on the time of onset and duration of AMS episodes, AMS data may be interpreted as a surrogate marker of ATAs recurrence. Recently, stored electrograms corresponding to episodes of ATAs have been introduced, thus clarifying the accuracy of AMS in detecting ATAs Clinically this information may be used to assess the efficacy of an antiarrhythmic intervention or the risk of thromboembolic events, and it may serve as a valuable research tool for evaluating the natural history and burden of ATAs
Exploring Convergence in some OECD Public Social Expenditure Trends
Triggered by the phenomenon of globalisation, during recent years there has been a process of State policy rationalisation in the social expenditure domain; hence the debate over the present role and dimension of welfare state has intensified. Following on the extensive multidisciplinary literature on this issue, the purpose of this paper is two-fold 1) to apply a more traditional analysis of convergence (sigma and beta convergence) in public social expenditures and 2) to analyse public social expenditure allocation expressed as a % of GDP and derive a possible classification of the countries by means of a multivariate approach. We conclude by explaining some similarities in the expenditure behaviour of certain countries in terms of the policy transfer process. Our results can be interpreted as a further contribution to the literature on contemporary public policy evaluation in the welfare domain.Policy Making, Welfare Programme, Public social Expenditures, Policy Transfer, principal component analysis, cluster analysis
A New 3D Tool for Planning Plastic Surgery
Face plastic surgery (PS) plays a major role in today medicine. Both for reconstructive and cosmetic surgery, achieving harmony of facial features is an important, if not the major goal. Several systems have been proposed for presenting to patient and surgeon possible outcomes of the surgical procedure. In this paper, we present a new 3D system able to automatically suggest, for selected facial features as nose, chin, etc, shapes that aesthetically match the patient's face. The basic idea is suggesting shape changes aimed to approach similar but more harmonious faces. To this goal, our system compares the 3D scan of the patient with a database of scans of harmonious faces, excluding the feature to be corrected. Then, the corresponding features of the k most similar harmonious faces, as well as their average, are suitably pasted onto the patient's face, producing k+1 aesthetically effective surgery simulations. The system has been fully implemented and tested. To demonstrate the system, a 3D database of harmonious faces has been collected and a number of PS treatments have been simulated. The ratings of the outcomes of the simulations, provided by panels of human judges, show that the system and the underlying idea are effectiv
MPC-based humanoid pursuit-evasion in the presence of obstacles
We consider a pursuit-evasion problem between humanoids in the presence of obstacles. In our scenario, the pursuer enters the safety area of the evader headed for collision, while the latter executes a fast evasive motion. Control schemes are designed for both the pursuer and the evader. They are structurally identical, although the objectives are different: the pursuer tries to align its direction of motion with the line- of-sight to the evader, whereas the evader tries to move in a direction orthogonal to the line-of-sight to the pursuer. At the core of the control architecture is a Model Predictive Control scheme for generating a stable gait. This allows for the inclusion of workspace obstacles, which we take into account at two levels: during the determination of the footsteps orientation and as an explicit MPC constraint. We illustrate the results with simulations on NAO humanoids
Correction of Italian under-reporting in the first COVID-19 wave via age-specific deconvolution of hospital admissions
When the COVID-19 pandemic first emerged in early 2020, healthcare and
bureaucratic systems worldwide were caught off guard and largely unprepared to
deal with the scale and severity of the outbreak. In Italy, this led to a
severe underreporting of infections during the first wave of the spread. The
lack of accurate data is critical as it hampers the retrospective assessment of
nonpharmacological interventions, the comparison with the following waves, and
the estimation and validation of epidemiological models. In particular, during
the first wave, reported cases of new infections were strikingly low if
compared with their effects in terms of deaths, hospitalizations and intensive
care admissions. In this paper, we observe that the hospital admissions during
the second wave were very well explained by the convolution of the reported
daily infections with an exponential kernel. By formulating the estimation of
the actual infections during the first wave as an inverse problem, its solution
by a regularization approach is proposed and validated. In this way, it was
possible to computed corrected time series of daily infections for each age
class. The new estimates are consistent with the serological survey published
in June 2020 by the National Institute of Statistics (ISTAT) and can be used to
speculate on the total number of infections occurring in Italy during 2020,
which appears to be about double the number officially recorded.Comment: 19 pages, 4 main figures, 2 supplementary figures, 2 table
Humanoid gait generation for walk-to locomotion using single-stage MPC
We consider the problem of gait generation for a humanoid robot that must walk to an assigned Cartesian goal. As a first solution, we consider a rather straightforward adaptation of our previous work: An external block produces high-level velocities, which are then tracked by a double-stage intrinsically stable MPC scheme where the orientation of the footsteps is chosen before determining their location and the CoM trajectory. The second solution, which represents the main contribution of the paper, is conceptually different: no high-level velocity is generated, and footstep orientations are chosen at the same time of the other decision variables in a singlestage MPC. This is made possible by carefully redesigning the motion constraints so as to preserve linearity. Preliminary results on a simulated NAO confirm that the single-stage method outperforms the conventional double-stage scheme
The perception of psychosocial risks and work-related stress in relation to job insecurity and gender differences: a cross-sectional study
Introduction.The perception of psychosocial risks exposesworkers to developwork-related stress. Recently the attention of scientific
research has focused on a psychosocial risk already identified as “job insecurity” that regards the “overall concern about the
continued existence of the job in the future” and that also depends onworker’s perception, different for each gender. Aimof the Study.
The aim of this cross sectional study is to show if job insecurity, in the formof temporary contracts, can influence the perception of
psychosocial risks and therefore increase worker’s vulnerability to work-related stress and how the magnitude of this effect differs
between genders. Materials and Methods. 338 administrative technical workers (113 males and 225 females) were administered a
questionnaire, enquiring contract typology (permanent or temporary contracts), and the Health Safety Executive questionnaire
to assess work-related stress. The Health Safety Executive Analysis Tool software was used to process collected questionnaires
and theWilcoxon rank-sum test was used to evaluate the statistical significance of the differences obtained. Results. Workers with
temporary contracts obtained lower scores than workers with permanent contracts in all the domains explored by theHealth Safety
Executive Analysis questionnaire, statistically significant (P<0,05). The female workers obtained lower scores than male workers in
all domains explored by the Health Safety Executive questionnaire. Conclusions. Authors conclude that perception of psychosocial
risks can be influenced by job insecurity, in the form of temporary contracts, and increases worker’s vulnerability to work-related
stress and differs between genders
IEEE 802.15.4e: a Survey
Several studies have highlighted that the IEEE 802.15.4 standard presents a number of limitations such as low reliability, unbounded packet delays and no protection against interference/fading, that prevent its adoption in applications with stringent requirements in terms of reliability and latency. Recently, the IEEE has released the 802.15.4e amendment that introduces a number of enhancements/modifications to the MAC layer of the original standard in order to overcome such limitations. In this paper we provide a clear and structured overview of all the new 802.15.4e mechanisms. After a general introduction to the 802.15.4e standard, we describe the details of the main 802.15.4e MAC behavior modes, namely Time Slotted Channel Hopping (TSCH), Deterministic and Synchronous Multi-channel Extension (DSME), and Low Latency Deterministic Network (LLDN). For each of them, we provide a detailed description and highlight the main features and possible application domains. Also, we survey the current literature and summarize open research issues
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