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Nonequilibrium dressing in a cavity with a movable reflecting mirror
Armata, Federico,Kim, M. S.,Butera, Salvatore,Rizzuto, Lucia,Passante, Roberto American Physical Society 2017 Physical Review D Vol.96 No.4
<P>We consider a movable mirror coupled to a one-dimensional massless scalar field in a cavity. Both the field and the mirror's mechanical degrees of freedom are described quantum mechanically, and they can interact with each other via the radiation pressure operator. We investigate the dynamical evolution of mirror and field starting from a nonequilibrium initial state, and their local interaction which brings the system to a stationary configuration for long times. This allows us to study the time-dependent dressing process of the movable mirror interacting with the field, and its dynamics leading to a local equilibrium dressed configuration. Also, in order to explore the effect of the radiation pressure on both sides of the movable mirror, we generalize the effective field-mirror Hamiltonian and previous results to the case of two cavities sharing the same mobile boundary. This leads us to address, in the appropriate limit, the dynamical dressing problem of a single mobile wall, bounded by a harmonic potential, in the vacuum space.</P>
Long versus Short Segment Instrumentation in Osteoporotic Thoracolumbar Vertebral Fracture
Girardo Massimo,Massè Alessandro,Risitano Salvatore,Fusini Federico 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.4
Study DesignRetrospective comparative study.PurposeThis study aimed to compare clinical and radiological data and rate of mechanical complications in elderly patients treated with short segment (SSS) or long segment stabilization (LSS) for thoracolumbar junction osteoporotic vertebral fractures (OVFs).Overview of LiteratureA fervent debate is now focused on the treatment of OVF using SSS or LSS. High rate of complications is associated with pedicle screw fixation because of poor bone quality.MethodsPatients over 65 years old with a T-score of <−2.5, affected by (T10–L2) vertebral fracture treated with LSS or SSS pedicle screw fixation, with at least 24 months of follow-up were evaluated. All patients were analyzed with conventional X-ray to evaluate bisegmental kyphotic angle (BKA) and clinically with Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and rate of mechanical complications at 2, 6, 12, and 24 months. Data were expressed as mean±standard deviation. Student t-test was used to compare clinical scores between populations. Mann-Whitney U-test was used to analyze clinical and radiological variable, whereas Fisher’s exact test was used to identify differences in the rate of complications between groups.ResultsA total of 37 patients met the inclusion criteria. Mean follow-up was 33.97±9.26 months. For both groups, ODI and VAS significantly decreased over time with good results (p<0.00001). At the final follow-up, no significant differences were found in terms of ODI and VAS. There was no difference in correction of BKA between groups; however, a significant difference was found in LSS group between pre- and postoperative BKA (p=0.046), whereas no difference was found in SSS group. A significant difference in the rate of mechanical complications was found between groups (p=0.011).ConclusionsBoth treatments showed good clinical and radiological results; however, LSS group showed better BKA correction and lower mechanical complications than SSS group.
Multi-Agent Quality of Experience Control
Francesco Delli Priscoli,Alessandro Di Giorgio,Federico Lisi,Salvatore Monaco,Antonio Pietrabissa,Vincenzo Suraci,Lorenzo Ricciardi Celsi 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.2
In the framework of the Future Internet, the aim of the Quality of Experience (QoE) Control functionalitiesis to track the personalized desired QoE level of the applications. The paper proposes to perform such a taskby dynamically selecting the most appropriate Classes of Service (among the ones supported by the network), thisselection being driven by a novel heuristic Multi-Agent Reinforcement Learning (MARL) algorithm. The papershows that such an approach offers the opportunity to cope with some practical implementation problems: in particular,it allows to face the so-called “curse of dimensionality” of MARL algorithms, thus achieving satisfactoryperformance results even in the presence of several hundreds of Agents.