Characterizing application scheduling on edge,fog, and cloud computing resources

Cloud computing has grown to become a popular distributed computing service offered by commercial providers. More recently, edge and fog computing resources have emerged on the wide-area network as part of Internet of things (IoT) deployments. These three resource abstraction layers are complementary, and offer distinctive benefits. Scheduling applications on clouds has been an active area of research, with workflow and data flow models offering a flexible abstraction to specify applications for execution. However, the application programming and scheduling models for edge and fog are still maturing, and can benefit from learnings on cloud resources. At the same time, there is also value in using these resources cohesively for application execution. In this article, we offer a taxonomy of concepts essential for specifying and solving the problem of scheduling applications on edge, fog, and cloud computing resources. We first characterize the resource capabilities and limitations of these infrastructure and offer a taxonomy of application models, quality-of-service constraints and goals, and scheduling techniques, based on a literature review. We also tabulate key research prototypes and papers using this taxonomy. This survey benefits developers and researchers on these distributed resources in designing and categorizing their applications, selecting the relevant computing abstraction(s), and developing or selecting the appropriate scheduling algorithm. It also highlights gaps in literature where open problems remain.     

Bacteria-Responsive Multidrug Delivery Nanosystem for Combating Long-Term Biofilm-Associated Infections

Microbial biofilm formation on implantable devices causes chronic infections that cannot be treated with existing antimicrobials. Quorum sensing inhibitors (QSIs) have recently emerged as novel antimicrobials for the prevention of biofilm formation. But blocking QS alone is insufficient to inhibit biofilm-associated chronic infections. Herein, chitosan hollow nanospheres are capped by bacteria-responsive β-casein to form a synergistic antifouling nanosystem consisting of a QSI and bactericide. β-casein is degraded by protease in a bacteria-colonized microenvironment in situ thus, QSI and bactericide are released sequentially. The release of QSI sensitises bacteria effectively through reduction of surface hydrophobicity, eDNA content, and lipopolysaccharide production in biofilms, amplifying the chemotherapeutic action of the bactericide. Compared to the uncoated surface, the coated surface inhibits biofilm formation and removes preformed biofilms of Pseudomonas aeruginosa PAO1 and methicillin-resistant Staphylococcus aureus by 1.8 logs and 1.9 logs of biomass inhibition, respectively. The coated catheters are found to stay clean for 30 days under artificial urine flow, while the uncoated catheters are clogged by bacterial biofilms within 5 days. Finally, the long term antifouling activity in vivo is confirmed. Overall, the nanosystem is devoted to making urinary catheters resistant to bacterial biofilm formation for the long term.