9 research outputs found
A multidisciplinary approach to the development of low-cost high-performance lightwave networks
Our research focuses on high-speed distributed systems. We anticipate that our results will allow the fabrication of low-cost networks employing multi-gigabit-per-second data links for space and military applications. The recent development of high-speed low-cost photonic components and new generations of microprocessors creates an opportunity to develop advanced large-scale distributed information systems. These systems currently involve hundreds of thousands of nodes and are made up of components and communications links that may fail during operation. In order to realize these systems, research is needed into technologies that foster adaptability and scaleability. Self-organizing mechanisms are needed to integrate a working fabric of large-scale distributed systems. The challenge is to fuse theory, technology, and development methodologies to construct a cost-effective, efficient, large-scale system
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AN OPTIMIZATION STAGE FOR AHPL COMPILER (LAYOUT).
The dissertation is a description of an analysis and a case study of an Optimization Stage for a Standard Cell oriented silicon compiler. Using the AHPL hardware description language, a complete representation hierarchy (functional, logic, and layout) is proposed for circuits defined at a Register Transfer level. The design of a new class of methods for layout analysis and optimization is based on this hierarchy. A layout evaluation method is based on the analysis of an activity graph derived from a circuit layout. The cost measure for such a graph is defined and used in evaluation of the necessary and sufficient conditions for design optimality (NSCDO). Iterations within the optimization process are controlled using a synthetic measure derived from these optimality conditions. A proposed layout optimization heuristic, derived from NSCDO, allows for better routing channel area utilization without compromising a circuit's timing performance. It is based on an analysis of the timing behavior modifications introduced by the various materials used as interconnectors resulting in an improvement of the load dependency of the output driving capabilities of cells. The dissertation contains an example of a quantitative analysis of a CMOS digital circuit. A system implementing some of the algorithms described above has been written in FORTRAN77
Simulation and Control of Reactive Systems
WeintroduceSIDE(theacronymstandsforSensors InaDistributedEnvironment)---asoftwarepackage fordevelopingcontrolprogramsforreactivesystems. OnedistinctivefeatureofSIDEisthatitcanbeused asasimulator:some(orevenall)componentsofthe underlyingphysicalnetworkcanbevirtual.Notably, thecontrolprogramitselfneednotbeawarethat somepartsofitsenvironmentarenotreal.SIDE applicationscanbenaturallydistributedandinterconnectedviatheInternet.
Post-anaesthesia pulmonary complications after use of muscle relaxants (POPULAR): a multicentre, prospective observational study
Background Results from retrospective studies suggest that use of neuromuscular blocking agents during general
anaesthesia might be linked to postoperative pulmonary complications. We therefore aimed to assess whether the use
of neuromuscular blocking agents is associated with postoperative pulmonary complications.
Methods We did a multicentre, prospective observational cohort study. Patients were recruited from 211 hospitals in
28 European countries. We included patients (aged ≥18 years) who received general anaesthesia for any in-hospital
procedure except cardiac surgery. Patient characteristics, surgical and anaesthetic details, and chart review at discharge
were prospectively collected over 2 weeks. Additionally, each patient underwent postoperative physical examination
within 3 days of surgery to check for adverse pulmonary events. The study outcome was the incidence of postoperative
pulmonary complications from the end of surgery up to postoperative day 28. Logistic regression analyses were
adjusted for surgical factors and patients’ preoperative physical status, providing adjusted odds ratios (ORadj) and
adjusted absolute risk reduction (ARRadj). This study is registered with ClinicalTrials.gov, number NCT01865513.
Findings Between June 16, 2014, and April 29, 2015, data from 22803 patients were collected. The use of neuromuscular
blocking agents was associated with an increased incidence of postoperative pulmonary complications in patients who
had undergone general anaesthesia (1658 [7·6%] of 21694); ORadj 1·86, 95% CI 1·53–2·26; ARRadj –4·4%, 95% CI
–5·5 to –3·2). Only 2·3% of high-risk surgical patients and those with adverse respiratory profiles were anaesthetised
without neuromuscular blocking agents. The use of neuromuscular monitoring (ORadj 1·31, 95% CI 1·15–1·49;
ARRadj –2·6%, 95% CI –3·9 to –1·4) and the administration of reversal agents (1·23, 1·07–1·41; –1·9%, –3·2 to –0·7)
were not associated with a decreased risk of postoperative pulmonary complications. Neither the choice of sugammadex
instead of neostigmine for reversal (ORadj 1·03, 95% CI 0·85–1·25; ARRadj –0·3%, 95% CI –2·4 to 1·5) nor extubation at
a train-of-four ratio of 0·9 or more (1·03, 0·82–1·31; –0·4%, –3·5 to 2·2) was associated with better pulmonary outcomes.
Interpretation We showed that the use of neuromuscular blocking drugs in general anaesthesia is associated with an
increased risk of postoperative pulmonary complications. Anaesthetists must balance the potential benefits of
neuromuscular blockade against the increased risk of postoperative pulmonary complications