The Price of Safety in an Active Network

Security is a major challenge for "Active Networking," accessible programmability creates numerous opportunities for mischief. The point at which programmability is exposed, e.g., through the loading and execution of code in network elements, must therefore be carefully crafted to ensure security. The SwitchWare active networking research project has studied the architectural implications of various tradeoffs between performance and security. Namespace protection and type safety were achieved with a module loader for active networks, ALIEN, which carefully delineated boundaries for privilege and dynamic updates. ALIEN supports two extensions, the Secure Active Network Environment (SANE), and the Resource Controlled Active Network Environment (RCANE). SANE extends ALIEN's node protection model into a distributed setting, and uses a secure bootstrap to guarantee integrity of the namespace protection system. RCANE provides resource isolation between active network node users, including separate heaps and robust time-division multiplexing of the node. The SANE and RCANE systems show that convincing active network security can be achieved. This paper contributes a measurement-based analysis of the costs of such security with an analysis of each system based on both execution traces and end-to-end behavior

The purple line as a measure of labour progress: a longitudinal study

Background: Vaginal examination (VE) and assessment of the cervix is currently considered to be the gold standard for assessment of labour progress. It is however inherently imprecise with studies indicating an overall accuracy for determining the diameter of the cervix at between 48-56%. Furthermore, VEs can be unpleasant, intrusive and embarrassing for women, and are associated with the risk of introducing infection. In light of increasing concern world wide about the use of routine interventions in labour it may be time to consider alternative, less intrusive means of assessing progress in labour. The presence of a purple line during labour, seen to rise from the anal margin and extend between the buttocks as labour progresses has been reported. The study described in this paper aimed to assess in what percentage of women in labour a purple line was present, clear and measurable and to determine if any relationship existed between the length of the purple line and cervical dilatation and/or station of the fetal head. Methods: This longitudinal study observed 144 women either in spontaneous labour (n=112) or for induction of labour (n=32) from admission through to final VE. Women were examined in the lateral position and midwives recorded the presence or absence of the line throughout labour immediately before each VE. Where present, the length of the line was measured using a disposable tape measure. Within subjects correlation, chi-squared test for independence, and independent samples t-test were used to analyse the data. Results: The purple line was seen at some point in labour for 109 women (76%). There was a medium positive correlation between length of the purple line and cervical dilatation (r=+0.36, n=66, P=0.0001) and station of the fetal head (r=+0.42, n=56, P<0.0001). Conclusions: The purple line does exist and there is a medium positive correlation between its length and both cervical dilatation and station of the fetal head. Where the line is present, it may provide a useful guide for clinicians of labour progress along side other measures. Further research is required to assess whether measurement of the line is acceptable to women in labour and also clinicians

A design space for dynamic service level agreements in OpenStack

© 2014, Lee and Sill; licensee Springer. cc-byThis paper does a systematic review of the possible design space for cloud-hosted applications that may have changing resource requirements that need to be supported through dynamic service level agreements (SLAs).The fundamental SLA functions are reviewed: Admission Control, Monitoring, SLA Evaluation, and SLA Enforcement – a classic autonomic control cycle.This is followed by an investigation into possible application requirements and SLA enforcement mechanisms.We then identify five basic Load Types that a dynamic SLA system must manage: Best Effort, Throttled, Load Migration, Preemption and Spare Capacity.The key to meeting application SLA requirements under changing surge conditions is to also manage the spare surge capacity.The use of this surge capacity could be managed by one of several identified load migration policies.A more detailed SLA architecture is presented that discusses specific SLA components.This is done in the context of the OpenStack since it is open source with a known architecture.Based on this SLA architecture, a research and development plan is presented wherein fundamental issues are identified that need to be resolved through research and experimentation.Based on successful outcomes, further developments are considered in the plan to produce a complete, end-to-end dynamic SLA capability.Executing on this plan will take significant resources and organization.The NSF Center for Cloud and Autonomic Computing is one possible avenue for pursuing these efforts.Given the growing importance of cloud performance management in the wider marketplace, the cloud community would be well-served to coordinate cloud SLA development across organizations such as the IEEE, Open Grid Forum, and the TeleManagement Forum

Epidemiology of surgery associated acute kidney injury (EPIS-AKI) : a prospective international observational multi-center clinical study

The incidence, patient features, risk factors and outcomes of surgery-associated postoperative acute kidney injury (PO-AKI) across different countries and health care systems is unclear. We conducted an international prospective, observational, multi-center study in 30 countries in patients undergoing major surgery (> 2-h duration and postoperative intensive care unit (ICU) or high dependency unit admission). The primary endpoint was the occurrence of PO-AKI within 72 h of surgery defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Secondary endpoints included PO-AKI severity and duration, use of renal replacement therapy (RRT), mortality, and ICU and hospital length of stay. We studied 10,568 patients and 1945 (18.4%) developed PO-AKI (1236 (63.5%) KDIGO stage 1500 (25.7%) KDIGO stage 2209 (10.7%) KDIGO stage 3). In 33.8% PO-AKI was persistent, and 170/1945 (8.7%) of patients with PO-AKI received RRT in the ICU. Patients with PO-AKI had greater ICU (6.3% vs. 0.7%) and hospital (8.6% vs. 1.4%) mortality, and longer ICU (median 2 (Q1-Q3, 1-3) days vs. 3 (Q1-Q3, 1-6) days) and hospital length of stay (median 14 (Q1-Q3, 9-24) days vs. 10 (Q1-Q3, 7-17) days). Risk factors for PO-AKI included older age, comorbidities (hypertension, diabetes, chronic kidney disease), type, duration and urgency of surgery as well as intraoperative vasopressors, and aminoglycosides administration. In a comprehensive multinational study, approximately one in five patients develop PO-AKI after major surgery. Increasing severity of PO-AKI is associated with a progressive increase in adverse outcomes. Our findings indicate that PO-AKI represents a significant burden for health care worldwide