Joint Time-and Event-Triggered Scheduling in the Linux Kernel

There is increasing interest in using Linux in the real-time domain due to the emergence of cloud and edge computing, the need to decrease costs, and the growing number of complex functional and non-functional requirements of real-time applications. Linux presents a valuable opportunity as it has rich hardware support, an open-source development model, a well-established programming environment, and avoids vendor lock-in. Although Linux was initially developed as a general-purpose operating system, some real-time capabilities have been added to the kernel over many years to increase its predictability and reduce its scheduling latency. Unfortunately, Linux currently has no support for time-triggered (TT) scheduling, which is widely used in the safety-critical domain for its determinism, low run-time scheduling latency, and strong isolation properties. We present an enhancement of the Linux scheduler as a new low-overhead TT scheduling class to support offline table-driven scheduling of tasks on multicore Linux nodes. Inspired by the Slot shifting algorithm, we complement the new scheduling class with a low overhead slot shifting manager running on a non-time-triggered core to provide guaranteed execution time to real-time aperiodic tasks by using the slack of the time-triggered tasks and avoiding high-overhead table regeneration for adding new periodic tasks. Furthermore, we evaluate our implementation on server-grade hardware with Intel Xeon Scalable Processor.Comment: to appear in Operating Systems Platforms for Embedded Real-Time applications (OSPERT) workshop 2023 co-hosted with 35th Euromicro conference on Real-time system

The Potential Applicability of Melatonin as an Immunosuppressive Agent for COVID-19: Review

COVID-19 is an emerging pathogen that has recently caused a global pandemic. It is an RNA virus that causes a respiratory tract infection. The pathogenesis of this virus involves an over aggressive immune reaction leading to inflammation and in certain cases acute respiratory distress syndrome (ARDS) and various neurological manifestations. Melatonin, a mitochondrially targeted antioxidant with anti-inflammatory properties, is being tested in trials as a potential adjuvant therapeutic agent that can help reduce oxidative stress damage caused by viral infections as well as optimizing the innate immune response. In addition, melatonin is an extremely safe drug and reports show its usefulness in treating other respiratory viral infections. The role of melatonin as an adjuvant in managing COVID-19 cases as well as the delirious states that are often encountered in these patients is being discussed

Mortality and pulmonary complications in patients undergoing surgery with perioperative sars-cov-2 infection: An international cohort study

Background The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (740%) had emergency surgery and 280 (248%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (261%) patients. 30-day mortality was 238% (268 of 1128). Pulmonary complications occurred in 577 (512%) of 1128 patients; 30-day mortality in these patients was 380% (219 of 577), accounting for 817% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 175 [95% CI 128-240], p<00001), age 70 years or older versus younger than 70 years (230 [165-322], p<00001), American Society of Anesthesiologists grades 3-5 versus grades 1-2 (235 [157-353], p<00001), malignant versus benign or obstetric diagnosis (155 [101-239], p=0046), emergency versus elective surgery (167 [106-263], p=0026), and major versus minor surgery (152 [101-231], p=0047). Interpretation Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Resource Management for Real-time and Mixed-Critical Systems

Multicore processors and Multiprocessor System-on-Chip (MPSoC) have become essential in Real-Time Systems (RTS) and Mixed-Criticality Systems (MCS) because of their additional computing capabilities that help reduce Size, Weight, and Power (SWaP), required wiring, and associated costs. In distributed systems, a single shared multicore or MPSoC node executes several applications, possibly of different criticality levels. However, there is interference between applications due to contention in shared resources such as CPU core, cache, memory, and network. Existing allocation and scheduling methods for RTS and MCS often rely on implicit assumptions of the constant availability of individual resources, especially the CPU, to provide guaranteed progress of tasks. Most existing approaches aim to resolve contention in only a specific shared resource or a set of specific shared resources. Moreover, they handle a limited number of events such as task arrivals and task completions. In distributed RTS and MCS with several nodes, each having multiple resources, if the applications, resource availability, or system configurations change, obtaining assumptions about resources becomes complicated. Thus, it is challenging to meet end-to-end constraints by considering each node, resource, or application individually. Such RTS and MCS need global resource management to coordinate and dynamically adapt system-wide allocation of resources. In addition, the resource management can dynamically adapt applications to changing availability of resources and maintains a system-wide (global) view of resources and applications. The overall aim of global resource management is twofold. Firstly, it must ensure real-time applications meet their end-to-end deadlines even in the presence of faults and changing environmental conditions. Secondly, it must provide efficient resource utilization to improve the Quality of Service (QoS) of co-executing Best-Effort (BE) (or non-critical) applications. A single fault in global resource management can render it useless. In the worst case, the resource management can make faulty decisions leading to a deadline miss in real-time applications. With the advent of Industry 4.0, cloud computing, and Internet-of-Things (IoT), it has become essential to combine stringent real-time constraints and reliability requirements with the need for an open-world assumption and ensure that the global resource management does not become an inviting target for attackers. In this dissertation, we propose a domain-independent global resource management framework for distributed RTS and MCS consisting of heterogeneous nodes based on multicore processors or MPSoC. We initially developed the framework with the French Aerospace Lab -- ONERA and Thales Research & Technology during the DREAMS project and later extended it during SECREDAS and other internal projects. Unlike previous resource management frameworks RTS and MCS, we consider both safety and security for the framework itself. To enable real-time industries to use cloud computing and enter a new market segment -- real-time operation as a cloud-based service, we propose a Real-Time-Cloud (RT-Cloud) based on global resource management for hosting RTS and MCS. Finally, we present a mixed-criticality avionics use case for evaluating the capabilities of the global resource management framework in handling permanent core failures and temporal overload condition, and a railway use case to motivate the use of RT-Cloud with global resource management

Resource Management for Real-time and Mixed-Critical Systems

Multicore processors and Multiprocessor System-on-Chip (MPSoC) have become essential in Real-Time Systems (RTS) and Mixed-Criticality Systems (MCS) because of their additional computing capabilities that help reduce Size, Weight, and Power (SWaP), required wiring, and associated costs. In distributed systems, a single shared multicore or MPSoC node executes several applications, possibly of different criticality levels. However, there is interference between applications due to contention in shared resources such as CPU core, cache, memory, and network. Existing allocation and scheduling methods for RTS and MCS often rely on implicit assumptions of the constant availability of individual resources, especially the CPU, to provide guaranteed progress of tasks. Most existing approaches aim to resolve contention in only a specific shared resource or a set of specific shared resources. Moreover, they handle a limited number of events such as task arrivals and task completions. In distributed RTS and MCS with several nodes, each having multiple resources, if the applications, resource availability, or system configurations change, obtaining assumptions about resources becomes complicated. Thus, it is challenging to meet end-to-end constraints by considering each node, resource, or application individually. Such RTS and MCS need global resource management to coordinate and dynamically adapt system-wide allocation of resources. In addition, the resource management can dynamically adapt applications to changing availability of resources and maintains a system-wide (global) view of resources and applications. The overall aim of global resource management is twofold. Firstly, it must ensure real-time applications meet their end-to-end deadlines even in the presence of faults and changing environmental conditions. Secondly, it must provide efficient resource utilization to improve the Quality of Service (QoS) of co-executing Best-Effort (BE) (or non-critical) applications. A single fault in global resource management can render it useless. In the worst case, the resource management can make faulty decisions leading to a deadline miss in real-time applications. With the advent of Industry 4.0, cloud computing, and Internet-of-Things (IoT), it has become essential to combine stringent real-time constraints and reliability requirements with the need for an open-world assumption and ensure that the global resource management does not become an inviting target for attackers. In this dissertation, we propose a domain-independent global resource management framework for distributed RTS and MCS consisting of heterogeneous nodes based on multicore processors or MPSoC. We initially developed the framework with the French Aerospace Lab -- ONERA and Thales Research & Technology during the DREAMS project and later extended it during SECREDAS and other internal projects. Unlike previous resource management frameworks RTS and MCS, we consider both safety and security for the framework itself. To enable real-time industries to use cloud computing and enter a new market segment -- real-time operation as a cloud-based service, we propose a Real-Time-Cloud (RT-Cloud) based on global resource management for hosting RTS and MCS. Finally, we present a mixed-criticality avionics use case for evaluating the capabilities of the global resource management framework in handling permanent core failures and temporal overload condition, and a railway use case to motivate the use of RT-Cloud with global resource management

Evaluation of DREAMS resource management solutions on a mixed-critical demonstrator

International audience—The paper describes the resource management developed within the DREAMS middleware and how it is able to support core failures and temporal overload situations. Those capabilities are then highlighted and assessed in the industrial mixed-critical demonstrator of the project.

Stem Cell Therapy for Post-Traumatic Stress Disorder: A Novel Therapeutic Approach

Stem cell therapy is a rapidly evolving field of regenerative medicine being employed for the management of various central nervous system disorders. The ability to self-renew, differentiate into specialized cells, and integrate into neuronal networks has positioned stem cells as an ideal mechanism for the treatment of epilepsy. Epilepsy is characterized by repetitive seizures caused by imbalance in the GABA and glutamate neurotransmission following neuronal damage. Stem cells provide benefit by reducing the glutamate excitotoxicity and strengthening the GABAergic inter-neuron connections. Similar to the abnormal neuroanatomic location in epilepsy, post-traumatic stress disorder (PTSD) is caused by hyperarousal in the amygdala and decreased activity of the hippocampus and medial prefrontal cortex. Thus, stem cells could be used to modulate neuronal interconnectivity. In this review, we provide a rationale for the use of stem cell therapy in the treatment of PTSD

Stem Cell Therapy for Post-Traumatic Stress Disorder: A Novel Therapeutic Approach

Stem cell therapy is a rapidly evolving field of regenerative medicine being employed for the management of various central nervous system disorders. The ability to self-renew, differentiate into specialized cells, and integrate into neuronal networks has positioned stem cells as an ideal mechanism for the treatment of epilepsy. Epilepsy is characterized by repetitive seizures caused by imbalance in the GABA and glutamate neurotransmission following neuronal damage. Stem cells provide benefit by reducing the glutamate excitotoxicity and strengthening the GABAergic inter-neuron connections. Similar to the abnormal neuroanatomic location in epilepsy, post-traumatic stress disorder (PTSD) is caused by hyperarousal in the amygdala and decreased activity of the hippocampus and medial prefrontal cortex. Thus, stem cells could be used to modulate neuronal interconnectivity. In this review, we provide a rationale for the use of stem cell therapy in the treatment of PTSD

A Comprehensive Review of the Neurological Manifestations of Celiac Disease and Its Treatment

Celiac disease (CD) is a common chronic inflammatory disorder occurring in genetically predisposed individuals secondary to gluten ingestion. CD usually presents with gastrointestinal symptoms such as pain, bloating, flatulence, and constipation or diarrhea. However, individuals can present in a nonclassical manner with only extraintestinal symptoms. The neurological manifestations of CD include ataxia, cognitive impairment, epilepsy, headache, and neuropathy. A lifelong gluten-free diet is the current recommended treatment for CD. This review discusses the relevant neurological manifestations associated with CD and the novel therapeutics. Further research is required to get a better understanding of the underlying pathophysiology of the neurological manifestations associated with CD. Clinicians should keep CD in the differential diagnosis in individuals presenting with neurological dysfunction of unknown cause