Tiling on systems with communication/computation overlap

In the framework of fully permutable loops, tiling is a compiler technique (also known as ‘loop blocking’) that has been extensively studied as a source-to-source program transformation. Little work has been devoted to the mapping and scheduling of the tiles on to physical parallel processors. We present several new results in the context of limited computational resources and assuming communication–computation overlap. In particular, under some reasonable assumptions, we derive the optimal mapping and scheduling of tiles to physical processors. Copyright © 1999 John Wiley & Sons, Ltd.     

On the Removal of Anti- and Output-Dependences

In this paper we build upon results of Padua and Wolfe, who introduced two graph transformations to break dependence paths including anti- and output-dependences. We first formalize these two transformations. Then, given a loop nest, we aim at determining which statements should be transformed so as to break artificial dependence paths involving anti- or output-dependences. The problem of finding the minimum number of statements to be transformed is shown to be NP-complete, and we propose two efficient heuristics.     

Crew resource management training for surgeons: feasibility and impact

This paper describes a prospective, within-subjects study to measure the before-after effect of training five general surgery attendings on crew resource management (CRM) strategies on the resultant use and perceived utility of those strategies. Subjects were trained via a 1-h lecture on seven CRM skills after their second observed case, and participated in a 15 min debriefing with the trainers immediately following their fourth through sixth observed cases. These interventions led to a significant increase in frequency (by 26–70%) of preoperative briefing elements over baseline. There was a significant correlation between the use of CRM practices and their perceived utility in improving team coordination and reducing error.     

On the structural complexity of a protein

The determination of the configuration of a protein in three-dimensional(3D) space constitutes one of the major challenges in molecularbiology research today. A method consists in choosing a proteinstructure from a database that minimizes an energy function.First, we model the problem in terms of dynamic programmingand show that the determination of the order in which the variablesmust be considered to minimize the time complexity is an NP-hardproblem. Second, we propose a new decomposition algorithm ofthe threading problem that is based on the connectivity of thegraph induced by the 3D structure of a protein. Our decompositioncould be used to solve the threading problem. The goal in thispaper is to evaluate the intrinsic complexity of 3D structure,which can be viewed as information that may be incorporatedinto a solution method. It provides two indexes of complexity(time and space) and determines in polynomial time complex componentsof the 3D structure of a protein.     

Circuit retiming applied to decomposed software pipelining

This paper elaborates on a new view on software pipelining, called decomposed software pipelining. The approach is to decouple the problem into resource constraints and dependence constraints. Resource constraints management amounts to scheduling an acyclic graph subject to resource constraints for which an efficiency bound is known, resulting in a bound for loop scheduling. The acyclic graph is obtained by cutting some particular edges of the (cyclic) dependence graph. In this paper, we cut edges in a different way, using circuit retiming algorithms, so as to minimize both the longest dependence path in the acyclic graph, and the number of edges in the acyclic graph. With this technique, we improve the efficiency bound given for Gasperoni and Schwlegelshohn algorithm, and we reduce the constraints that remain for the acyclic problem. We believe this framework to be of interest because it brings a new insight into the software problem by establishing its deep link with the circuit retiming problem     

Improving surgical pattern recognition through repetitive viewing of video clips

Previous field studies show that surgery residents and medical students have difficulty recognizing appropriate anatomic cues during laparoscopic surgery, causing delays in procedures and errors. Such observations led to the development of an anatomy recognition training intervention, specifically the use of an ordered set of video clips that show the main steps of a laparoscopic procedure. Each procedural step is shown several times in succession, with each repetition coming from a different surgery, thus exposing the learner to varied anatomy and crucial maneuvers. A factorial experiment with 30 medical students showed that the group using these ordered, perceptual learning modules had a significant increase in scores on questions assessing perceptual knowledge and procedural knowledge, with no corresponding increase for the control group who watched the videos from the same cases but in an unstructured format for the same amount of time (p< 0.05). Neither group showed improvement on strategic or declarative knowledge tests. The study suggests that ordered perceptual learning modules are a potential means for training perceptual and procedural knowledge in an effective, safe, and efficient manner, serving as a complement to other types of training methods that teach physical dexterity, strategic and declarative knowledge.     

Using video data for the analysis and training of medical personnel

This paper describes a set of studies that use audio–visual recording in an actual environment (surgery) to study the effectiveness of various patient safety interventions. Video is used in several different ways: as the intervention in one of the studies, and as a means to capture team behavior during surgeries for the other two studies. This paper summarises the logistical, legal, regulatory, technical, financial, social and methodological factors that must be considered and discusses solutions to many of these potential barriers. Although audio–visual recording has a long history in human factors research, only now are the technical, financial and logistic barriers less of a concern, as all data can now be stored and analysed electronically, making many previously cumbersome factors less so through the use of technology. Perhaps the most challenging areas that require more research are the methodological difficulties encountered when observing teams in an uncontrolled environment.