This survey covers research into mixed criticality systems that has been published since Vestal’s seminal paper in 2007, up until the end of 2016. The survey is organised along the lines of the major ...research areas within this topic. These include single processor analysis (including fixed priority and Earliest Deadline First (EDF) scheduling, shared resources, and static and synchronous scheduling), multiprocessor analysis, realistic models, and systems issues. The survey also explores the relationship between research into mixed criticality systems and other topics such as hard and soft time constraints, fault tolerant scheduling, hierarchical scheduling, cyber physical systems, probabilistic real-time systems, and industrial safety standards.
This survey covers hard real-time scheduling algorithms and schedulability analysis techniques for homogeneous multiprocessor systems. It reviews the key results in this field from its origins in the ...late 1960s to the latest research published in late 2009. The survey outlines fundamental results about multiprocessor real-time scheduling that hold independent of the scheduling algorithms employed. It provides a taxonomy of the different scheduling methods, and considers the various performance metrics that can be used for comparison purposes. A detailed review is provided covering partitioned, global, and hybrid scheduling algorithms, approaches to resource sharing, and the latest results from empirical investigations. The survey identifies open issues, key research challenges, and likely productive research directions.
Routine childhood immunizations are proven to be one of the most effective public health interventions at controlling numerous deadly diseases. Therefore, the CDC recommends routine immunizations for ...children and adolescent populations against vaccine-preventable diseases e.g., tetanus, pertussis, diphtheria, etc. This current review sought to examine barriers to pediatric vaccine uptake behaviors during the COVID-19 pandemic. We also explored the implications for parental vaccine hesitancy/delay during an ongoing health crisis and proposed recommendations for increasing vaccine confidence and compliance. Our review determined that the receipt for vaccinations steadily improved in the last decade for both the United States and Tennessee. However, this incremental progress has been forestalled by the COVID-19 pandemic and other barriers i.e. parental vaccine hesitancy, social determinants of health (SDoH) inequalities, etc. which further exacerbate vaccination disparities. Moreover, non-compliance to routine vaccinations could cause an outbreak of diseases, thereby, worsening the ongoing health crisis and already strained health care system. Healthcare providers are uniquely positioned to offer effective recommendations with presumptive languaging to increase vaccination rates, as well as, address parental vaccine hesitancy. Best practices that incorporate healthcare providers' quality improvement coaching, vaccination reminder recall systems, adherence to standardized safety protocols (physical distancing, hand hygiene practices, etc.), as well as, offer telehealth and outdoor/drive-through/curbside vaccination services, etc. are warranted. Additionally, a concerted effort should be made to utilize public health surveillance systems to collect, analyze, and interpret data, thereby, ensuring the dissemination of timely, accurate health information for effective health policy decision-making e.g., vaccine distribution, etc.
Robust Mixed-Criticality Systems Burns, Alan; Davis, Robert I.; Baruah, Sanjoy ...
IEEE transactions on computers,
10/2018, Letnik:
67, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Certification authorities require correctness and survivability. In the temporal domain this requires a convincing argument that all deadlines will be met under error free conditions, and that when ...certain defined errors occur the behaviour of the system is still predictable and safe. This means that occasional execution-time overruns should be tolerated and where more severe errors occur levels of graceful degradation should be supported. With mixed-criticality systems, fault tolerance must be criticality aware, i.e. some tasks should degrade less than others. In this paper a quantitative notion of robustness is defined, and it is shown how fixed priority-based task scheduling can be structured to maximise the likelihood of a system remaining fail operational or fail robust (the latter implying that an occasional job may be skipped if all other deadlines are met). Analysis is developed for fail operational and fail robust behaviour, optimal priority ordering is addressed and an experimental evaluation is described. Overall, the approach presented allows robustness to be balanced against schedulability. A designer would thus be able to explore the design space so defined.
As phytoplasmas are discovered at an ever-increasing pace in emerging and re-emerging plant diseases worldwide, the scheme for classification of phytoplasmas into 16S rRNA gene RFLP (16Sr) groups and ...subgroups is experiencing an ongoing rapid expansion. Improper delineation or designation of new groups and subgroups can open potential conflicts in classifying newly identified phytoplasma strains. To maintain the integrity of the classification scheme, criteria for the delineation of new groups and subgroups must be followed, and proper registration should be required to track established groups and subgroups.
Research examining associations between weather and human health frequently includes the effects of atmospheric humidity. A large number of humidity variables have been developed for numerous ...purposes, but little guidance is available to health researchers regarding appropriate variable selection. We examine a suite of commonly used humidity variables and summarize both the medical and biometeorological literature on associations between humidity and human health. As an example of the importance of humidity variable selection, we correlate numerous hourly humidity variables to daily respiratory syncytial virus isolates in Singapore from 1992 to 1994. Most water-vapor mass based variables (specific humidity, absolute humidity, mixing ratio, dewpoint temperature, vapor pressure) exhibit comparable correlations. Variables that include a thermal component (relative humidity, dewpoint depression, saturation vapor pressure) exhibit strong diurnality and seasonality. Humidity variable selection must be dictated by the underlying research question. Despite being the most commonly used humidity variable, relative humidity should be used sparingly and avoided in cases when the proximity to saturation is not medically relevant. Care must be taken in averaging certain humidity variables daily or seasonally to avoid statistical biasing associated with variables that are inherently diurnal through their relationship to temperature.
"Who were the First Americans? Where did they come from? When did they get here? Are they the ancestors of modern Native Americans? These questions might seem straightforward, but scientists in ...competing fields have failed to convince one another with their theories and evidence, much less Native American peoples. The practice of science in its search for the First Americans is a flawed endeavor, Robert V. Davis tells us. His book is an effort to explain why. Most American history textbooks today teach that the First Americans migrated to North America on foot from East Asia over a land bridge during the last ice age, 12,000 to 13,000 years ago. In fact, that theory hardly represents the scientific consensus, and it has never won many Native adherents. In many ways, attempts to identify the first Americans embody the conflicts in American society between accepting the practical usefulness of science and honoring cultural values. Davis explores how the contested definition of “First Americans” reflects the unsettled status of Native traditional knowledge, scientific theories, research methodologies, and public policy as they vie with one another for legitimacy in modern America. In this light he considers the traditional beliefs of Native Americans about their origins; the struggle for primacy—or even recognition as science—between the disciplines of anthropology and archaeology; and the mediating, interacting, and sometimes opposing influences of external authorities such as government agencies, universities, museums, and the press. Fossil remains from Mesa Verde, Clovis, and other sites testify to the presence of First Americans. What remains unsettled, as The Search for the First Americans makes clear, is not only who these people were, where they came from, and when, but also the very nature and practice of the science searching for answers. "
The selective oxidation of alcohols in aqueous phase over supported metal catalysts is facilitated by high-pH conditions. We have studied the mechanism of ethanol and glycerol oxidation to acids over ...various supported gold and platinum catalysts. Labeling experiments with ¹⁸O₂ and H₂¹⁸O demonstrate that oxygen atoms originating from hydroxide ions instead of molecular oxygen are incorporated into the alcohol during the oxidation reaction. Density functional theory calculations suggest that the reaction path involves both solution-mediated and metal-catalyzed elementary steps. Molecular oxygen is proposed to participate in the catalytic cycle not by dissociation to atomic oxygen but by regenerating hydroxide ions formed via the catalytic decomposition of a peroxide intermediate.
Ecological and life-history data on the Northern European macromoth (Lepidoptera: Macroheterocera) fauna is widely available and ideal for use in answering phylogeny-based research questions: for ...example, in comparative biology. However, phylogenetic information for such studies lags behind. Here, as a synthesis of all currently available phylogenetic information on the group, we produce a supertree of 114 Northern European macromoth genera (in four superfamilies, with Geometroidea considered separately), providing the most complete phylogenetic picture of this fauna available to date. In doing so, we assess those parts of the phylogeny that are well resolved and those that are uncertain. Furthermore, we identify those genera for which phylogenetic information is currently too poor to include in such a supertree, or entirely absent, as targets for future work. As an aid to studies involving these genera, we provide information on their likely positions within the macromoth tree. With phylogenies playing an ever more important role in the field, this supertree should be useful in informing future ecological and evolutionary studies.
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