Geocasting and Multicasting Routing Operation in Mobile Ad Hoc Network

Abstract: The paper considers, the different multicasting routing protocols in wireless mobile Ad hoc network (MANET).An Ad hoc network is composed of mobile nodes without the presence of a wired support infrastructure .In this environment routing/multicasting protocols are faced with the challenge of producing multihop router under host mobility and band constraints. Various approaches and routing protocol have been proposed to address Ad hoc networking problems and multiple standardization effort within the Internet Engineering Task Force, along with academic and industrial research projects. In recent year, a number of new multicast protocols of different styles have been proposed for Ad hoc networks. Geocast Adaptive Mesh Environment for Routing [GAMER] is one which provides geocast communication in an Ad hoc network and it adapts to the correct network environment by dynamically changing the density of the mesh. Forwarding Group Multicast Protocol [FGMP] is based on the forward group concept and it dynamically refreshes the forward group member using a procedure to On-Demand routing. The relative strengths, weakness and applicability of each multicast protocol to diverse situations have considered and analyzed. Index Terms: FGMP Protocol, GAMER Protocol, MANETs, multicast, routing. An Ad hoc networks [1] [2] , is a dynamically reconfigurable wireless network with no fixed infrastructure (or) central administration. Due to the limited radio propagation range of wireless devices, routers are often "multihop". Applications such as disaster recovery, crowd control, search, rescue and automated battlefields are typical examples of where Ad hoc networks are deployed. Nodes in these networks more arbitrary thus network topology changes frequently and unpredictably. Moreover, bandwidth and battery power are limited. These constraints, in combination with the dynamic network topology make routing and multicasting in Ad hoc networks extremely challenging. Various multicast protocols have been newly proposed to perform multicasting in Ad hoc network. However, no operation study between them has yet been performed. The comparative analysis of Ad hoc unicast routing protocols has been reported. This paper gives a comparison study of two protocols with different characteristics: GAMER [3] and FGMP The rest of the paper is organized as follows. Section I presents an overview of the multicast protocols. The section II discusses the future enhancements, and concluding remarks are made in section III.

Prospective observational cohort study on grading the severity of postoperative complications in global surgery research

Background The Clavien–Dindo classification is perhaps the most widely used approach for reporting postoperative complications in clinical trials. This system classifies complication severity by the treatment provided. However, it is unclear whether the Clavien–Dindo system can be used internationally in studies across differing healthcare systems in high- (HICs) and low- and middle-income countries (LMICs). Methods This was a secondary analysis of the International Surgical Outcomes Study (ISOS), a prospective observational cohort study of elective surgery in adults. Data collection occurred over a 7-day period. Severity of complications was graded using Clavien–Dindo and the simpler ISOS grading (mild, moderate or severe, based on guided investigator judgement). Severity grading was compared using the intraclass correlation coefficient (ICC). Data are presented as frequencies and ICC values (with 95 per cent c.i.). The analysis was stratified by income status of the country, comparing HICs with LMICs. Results A total of 44 814 patients were recruited from 474 hospitals in 27 countries (19 HICs and 8 LMICs). Some 7508 patients (16·8 per cent) experienced at least one postoperative complication, equivalent to 11 664 complications in total. Using the ISOS classification, 5504 of 11 664 complications (47·2 per cent) were graded as mild, 4244 (36·4 per cent) as moderate and 1916 (16·4 per cent) as severe. Using Clavien–Dindo, 6781 of 11 664 complications (58·1 per cent) were graded as I or II, 1740 (14·9 per cent) as III, 2408 (20·6 per cent) as IV and 735 (6·3 per cent) as V. Agreement between classification systems was poor overall (ICC 0·41, 95 per cent c.i. 0·20 to 0·55), and in LMICs (ICC 0·23, 0·05 to 0·38) and HICs (ICC 0·46, 0·25 to 0·59). Conclusion Caution is recommended when using a treatment approach to grade complications in global surgery studies, as this may introduce bias unintentionally

The surgical safety checklist and patient outcomes after surgery: a prospective observational cohort study, systematic review and meta-analysis

© 2017 British Journal of Anaesthesia Background: The surgical safety checklist is widely used to improve the quality of perioperative care. However, clinicians continue to debate the clinical effectiveness of this tool. Methods: Prospective analysis of data from the International Surgical Outcomes Study (ISOS), an international observational study of elective in-patient surgery, accompanied by a systematic review and meta-analysis of published literature. The exposure was surgical safety checklist use. The primary outcome was in-hospital mortality and the secondary outcome was postoperative complications. In the ISOS cohort, a multivariable multi-level generalized linear model was used to test associations. To further contextualise these findings, we included the results from the ISOS cohort in a meta-analysis. Results are reported as odds ratios (OR) with 95% confidence intervals. Results: We included 44 814 patients from 497 hospitals in 27 countries in the ISOS analysis. There were 40 245 (89.8%) patients exposed to the checklist, whilst 7508 (16.8%) sustained ≥1 postoperative complications and 207 (0.5%) died before hospital discharge. Checklist exposure was associated with reduced mortality [odds ratio (OR) 0.49 (0.32–0.77); P\u3c0.01], but no difference in complication rates [OR 1.02 (0.88–1.19); P=0.75]. In a systematic review, we screened 3732 records and identified 11 eligible studies of 453 292 patients including the ISOS cohort. Checklist exposure was associated with both reduced postoperative mortality [OR 0.75 (0.62–0.92); P\u3c0.01; I2=87%] and reduced complication rates [OR 0.73 (0.61–0.88); P\u3c0.01; I2=89%). Conclusions: Patients exposed to a surgical safety checklist experience better postoperative outcomes, but this could simply reflect wider quality of care in hospitals where checklist use is routine

Critical care admission following elective surgery was not associated with survival benefit: prospective analysis of data from 27 countries

This was an investigator initiated study funded by Nestle Health Sciences through an unrestricted research grant, and by a National Institute for Health Research (UK) Professorship held by RP. The study was sponsored by Queen Mary University of London