Explicit Reference Governor for Continuous Time Nonlinear Systems Subject to Convex Constraints

This paper introduces a novel closed-form strategy that dynamically modifies the reference of a pre-compensated nonlinear system to ensure the satisfaction of a set of convex constraints. The main idea consists of translating constraints in the state space into constraints on the Lyapunov function and then modulating the reference velocity so as to limit the value of the Lyapunov function. The theory is introduced for general nonlinear systems subject to convex constraints. In the case of polyhedric constraints, an explicit solution is provided for the large and highly relevant class of nonlinear systems whose Lyapunov function is lower-bounded by a quadratic form. In view of improving performances, further specializations are provided for the relevant cases of linear systems and robotic manipulators.Comment: Submitted to: IEEE Transactions on Automatic Contro

Using Dynamic Safety Margins as Control Barrier Functions

This paper provides an approach to design control barrier functions (CBFs) using the notion of dynamic safety margins (DSMs). In particular, it is shown that DSMs are CBFs for an augmented system. The proposed approach can handle multiple state and input constraints using the control-sharing property of CBFs. Moreover, it makes no assumption on the relative degree of the constraints. Numerical simulations show that the method outperforms existing DSM-based approaches, while also guaranteeing safety and recursive feasibility.Comment: 7 pages, 2 figure

Finite-Time Computation of Polyhedral Input-Saturated Output-Admissible Sets

The paper introduces a novel algorithm for computing the output admissible set of linear discrete-time systems subject to input saturation. The proposed method takes advantage of the piecewise-affine dynamics to propagate the output constraints within the non-saturated and saturated regions. The constraints are then shared between regions to ensure a proper transition from one region to another. The resulting algorithm generates a set that is proven to be polyhedral, safe, positively invariant, and finitely determined. Moreover, the set is also proven to be strictly larger than the maximal output admissible set that would be obtained by treating input saturation as a constraint.Comment: Submitted to IEEE Transactions on Automatic Contro

Hybrid protoneutron stars with the MIT bag model

We study the hadron-quark phase transition in the interior of protoneutron stars. For the hadronic sector, we use a microscopic equation of state involving nucleons and hyperons derived within the finite-temperature Brueckner-Bethe-Goldstone many-body theory, with realistic two-body and three-body forces. For the description of quark matter, we employ the MIT bag model both with a constant and a density-dependent bag parameter. We calculate the structure of protostars with the equation of state comprising both phases and find maximum masses below 1.6 solar masses. Metastable heavy hybrid protostars are not found.Comment: 12 pages, 9 figures submitted to Phys. Rev.

Teacher Satisfaction in Relationships With Students and Parents and Burnout

In the educational field, the role of the support component of the teacher-student relationship is well known, while the role of the teacher-student relationship on teacher burnout is a more current field of investigation. Several studies on the sources of burnout have recently focused on job satisfaction and teacher-student satisfaction. However, the role of teacher-parent satisfaction is still little explored in this field. Moreover, in the Italian school context, students’ seniority and educational level require further investigation, as the average age of teachers is particularly high compared to their European colleagues. The present study aims to examine in a sample of 882 Italian teachers the presence of burnout and differences in teacher-student and teacher-parent satisfaction between primary (students aged 6–10years) and lower secondary (students aged 11–13years) teachers. A further objective is to test whether teacher-student and teacher-parent satisfaction and seniority can be significant predictors of burnout. Teachers completed the Job Satisfaction Scale (MESI) and the MBI-Educators Survey and the data were then processed using MANOVA and multiple linear regression analysis. The results revealed that 8.2% of the teachers suffered from burnout and lower secondary teachers showed the highest levels of emotional exhaustion, depersonalisation and reduced personal accomplishment. Predictors of emotional exhaustion were job dissatisfaction and seniority, and predictors of depersonalisation were job dissatisfaction and teacher-student dissatisfaction. Finally, predictors of personal accomplishment were also teacher-parent satisfaction and teacher-student satisfaction. The implications of these findings for practice and research are discussed in this article

How to solve Quantum Optimal Control Problems using Projection Operator-based Newton Steps

The Quantum PRojection Operator-based Newton method for Trajectory Optimization, a.k.a. Q-PRONTO, is a numerical method for solving quantum optimal control problems. This paper significantly improves prior versions of the quantum projection operator by introducing a regulator that stabilizes the solution estimate at every iteration. This modification is shown to not only improve the convergence rate of the algorithm, but also steer the solver towards better local minima compared to the un-regulated case. Numerical examples showcase Q-PRONTO can be used to solve multi-input quantum optimal control problems featuring time-varying costs and undesirable populations that ought to be avoided during the transient.Comment: 10 pages, 9 figure

A meta-analysis of the prevalence of common clinical characteristics in Velocardiofacial syndrome

Background: Velocardiofacial syndrome (VCFS) is a congenital malformation syndrome with an estimated prevalence of 1:4,000 livebirths. Most cases are caused by a common 3 Mb deletion at 22q11.2. This syndrome exhibits wide inter- and intra-familial variability in phenotypic features including physical, developmental, neurological, and neuropsychiatric manifestations despite the general uniformity in deletion size. The purpose of this meta-analysis was to seek explanations for the differences in the reported prevalence rates of various findings; to more accurately estimate the prevalence of each of the nine traits examined; to provide insight into future research; and to improve the ability for genetic counselors and clinicians to provide more appropriate services and offer appropriate resources. Methods: A PubMed search was performed for keywords associated with VCFS. After an exhaustive search, twenty-nine articles were included. Nine traits of interest were chosen along with five predictor variables. From the articles, prevalence data was abstracted, overall prevalence data was calculated, and unweighted and weighted regression analyses were performed. Results: Ascertainment bias may be associated with the prevalence of ADHD; the prevalence of males does not appear to play a role in the discrepant data; the number of years ago a study was published is associated with prevalence of ADHD, cleft palate, palatal findings and VPI; age range is associated with the prevalence of congenital heart defects; having a de novo deletion is significantly associated with the prevalence of cleft palate and SMCP; and geographical location is significantly associated with the prevalence of palatal anomalies. Overall prevalence rates are as follows: ADHD 17.2%, CHD 73.5%, cleft palate 11.6%, submucosal cleft palate 17.0%, velopharyngeal insufficiency 35.1%, any palatal anomaly 54.1%, any psychiatric disorder 34.4%, schizophrenia 12.6%, and hypotonia 64.5%. Conclusions: Due to small sample sizes, it is difficult to draw conclusions on the presented data; however, this analysis provides useful insight into future avenues of research especially with regards to behavioral and psychiatric illnesses. Many findings, especially psychiatric illnesses, associated with VCFS, pose a significant public health burden thus it would be of public health significance to find answers to some of the questions addressed in this study

Communications Biophysics

Contains reports on two research projects.United States Air Force (Contract AF19(604)-4112)United States Air Force, Office of Scientific Research, Air Research and Development Command (Contract AF 61 (052)-107)Rockefeller Foundatio