RT-Kubernetes - Containerized Real-Time Cloud Computing

This paper presents RT-Kubernetes, a software architecture with the ability to deploy real-time software components within containers in cloud infrastructures. The deployment of containers with guaranteed CPU scheduling is obtained by using a hierarchical real-time scheduler based on the Linux SCHED_DEADLINE policy. Preliminary experimental results provide evidence that this new framework succeeds in providing timeliness guarantees in the target responsiveness range, while achieving strong temporal isolation among containers co-located on the same physical hosts

Inclusive inelastic scattering of heavy ions and nuclear correlations

Calculations of inclusive inelastic scattering distributions for heavy ion collisions are considered within the high energy optical model. Using ground state sum rules, the inclusive projectile and complete projectile-target inelastic angular distributions are treated in both independent particle and correlated nuclear models. Comparisons between the models introduced are made for alpha particles colliding with He-4, C-12, and O-16 targets and protons colliding with O-16. Results indicate that correlations contribute significantly, at small momentum transfers, to the inelastic sum. Correlation effects are hidden, however, when total scattering distributions are considered because of the dominance of elastic scattering at small momentum transfers

Eikonal solutions to optical model coupled-channel equations

Methods of solution are presented for the Eikonal form of the nucleus-nucleus coupled-channel scattering amplitudes. Analytic solutions are obtained for the second-order optical potential for elastic scattering. A numerical comparison is made between the first and second order optical model solutions for elastic and inelastic scattering of H-1 and He-4 on C-12. The effects of bound-state excitations on total and reaction cross sections are also estimated

Implications of SARS-COV-2 infection in the diagnosis and management of the pediatric gastrointestinal disease

Gastrointestinal diseases such as celiac disease, functional gastrointestinal disorders (FGIDs), inflammatory bowel disease (IBDs) and acute or chronic diarrhea are quite frequent in the pediatric population. The approach, the diagnosis and management can be changed in the 2019 coronavirus disease (COVID-19) pandemic era. This review has focused on: i) the current understanding of digestive involvement in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected children and adolescents and the clinical implications of COVID-19 for pediatric gastroenterologists, ii) the impact of COVID-19 on the clinical approach to patients with pre-existing or onset diseases, including diagnosis and treatment, and iii) the role and limited access to the instrumental diagnosis such as digestive endoscopy. To date, it is unclear if immunosuppression in patients with IBD and chronic liver disease represents a risk factor for adverse outcomes. Scheduled outpatient follow-up visits may be postponed, especially in patients in remission. Conversely, telemedicine services are strongly recommended. The introduction of new therapeutic regimens should be made on an individual basis, discussing the benefits and risks with each patient. Furthermore, psychological care in all children with chronic disease and their parents should be ensured. All non-urgent and elective endoscopic procedures may be postponed as they must be considered at high risk of viral transmission. Finally, until SARS-CoV-2 vaccination is not available, strict adherence to standard social distancing protocols and the use of personal protective equipment should continue to be recommended

Simplified model for solar cosmic ray exposure in manned Earth orbital flights

A simple calculational model is derived for use in estimating solar cosmic ray exposure to critical body organs in low-Earth orbit at the center of a large spherical shield of fixed thickness. The effects of the Earth's geomagnetic field, including storm conditions and the astronauts' self-shielding, are evaluated explicitly. The magnetic storm model is keyed to the planetary index K(sub p)

A thread synchronization model for the PREEMPT_RT Linux kernel

This article proposes an automata-based model for describing and validating sequences of kernel events in Linux PREEMPT_RT and how they influence the timeline of threads’ execution, comprising preemption control, interrupt handling and control, scheduling and locking. This article also presents an extension of the Linux tracing framework that enables the tracing of kernel events to verify the consistency of the kernel execution compared to the event sequences that are legal according to the formal model. This enables cross-checking of a kernel behavior against the formalized one, and in case of inconsistency, it pinpoints possible areas of improvement of the kernel, useful for regression testing. Indeed, we describe in details three problems in the kernel revealed by using the proposed technique, along with a short summary on how we reported and proposed fixes to the Linux kernel community. As an example of the usage of the model, the analysis of the events involved in the activation of the highest priority thread is presented, describing the delays occurred in this operation in the same granularity used by kernel developers. This illustrates how it is possible to take advantage of the model for analyzing the preemption model of Linux

Dispersion engineering of highly nonlinear chalcogenide suspended-core fibers

Chalcogenide optical fibers are currently undergoing intensive investigation with the aim of exploiting the excellent glass transmission and nonlinear characteristics in the near- and mid-infrared for several applications. Further enhancement of these properties can be obtained, for a particular application, with optical fibers specifically designed that are capable of providing low effective area together with a properly tailored dispersion, matching the characteristics of the laser sources used to excite nonlinear effects. Suspended-core photonic crystal fibers are ideal candidates for nonlinear applications, providing small-core waveguides with large index contrast and tunable dispersion. In this paper, the dispersion properties of As2S3 suspended-core fibers are numerically analyzed, taking into account, for the first time, all the structural parameters, including the size and the number of the glass bridges. The results show that a proper design of the cladding struts can be exploited to significantly change the fiber properties, altering the maximum value of the dispersion parameter and shifting the zero-dispersion wavelengths over a range of 400 nm

Efficient Formal Verification for the Linux Kernel

Formal verification of the Linux kernel has been receiving increasing attention in recent years, with the development of many models, from memory subsystems to the synchronization primitives of the real-time kernel. The effort in developing formal verification methods is justified considering the large code-base, the complexity in synchronization required in a monolithic kernel and the support for multiple architectures, along with the usage of Linux on critical systems, from high-frequency trading to self-driven cars. Despite recent developments in the area, none of the proposed approaches are suitable and flexible enough to be applied in an efficient way to a running kernel. Aiming to fill such a gap, this paper proposes a formal verification approach for the Linux kernel, based on automata models. It presents a method to auto-generate verification code from an automaton, which can be integrated into a module and dynamically added into the kernel for efficient on-the-fly verification of the system, using in-kernel tracing features. Finally, a set of experiments demonstrate verification of three models, along with performance analysis of the impact of the verification, in terms of latency and throughput of the system, showing the efficiency of the approach

Tailoring the electronic properties of silicon with cysteine: A first principle study

We discuss the electronic structure modifications induced on the dihydride-terminated Si(001) surface upon cysteine adsorption by means of ab initio calculations: several stable functionalization schemes are presented, providing different routes for biological recognition, surface nanostructuring, and biomolecular electronics applications. The resulting hybrid systems are discussed and compared in terms of stability, structural, and electronic properties. Based on our results, we propose STM and photoemission experiments to determine unambiguously the adsorption mechanism involved and the attached functional group