Rethinking Space, Light, And Pedagogy

Classic

Shock reflection and surface effects in the shock tube

A thin-film resistance thermometer, mounted on the end-wall of a shock tube, is used to record surface temperatures and heat transfer rates following reflection of the primary shock wave. This information is combined with the results of theoretical investigations to produce simultaneous information about surface accommodation effects and gas thermal conductivities at high pressures and moderate temperatures

Book reviews

Teaching/Communication/Extension/Profession,

The use of collaboration to implement evidence-based safe practices

The Pennsylvania Patient Safety Authority receives over 235,000 reports of medical error per year. Near miss and serious event reports of common and interesting problems are analysed to identify best practices for preventing harmful errors. Dissemination of this evidence-based information in the peer-reviewed Pennsylvania Patient Safety Advisory and presentations to medical staffs are not sufficient for adoption of best practices. Adoption of best practices has required working with institutions to identify local barriers to and incentives for adopting best practices and redesigning the delivery system to make desired behaviour easy and undesirable behaviour more difficult. Collaborations, where institutions can learn from the experiences of others, have show decreases in harmful events. The Pennsylvania Program to Prevent Wrong-Site Surgery is used as an example. Two collaborations to prevent wrong-site surgery have been completed, one with 30 institutions in eastern Pennsylvania and one with 19 in western Pennsylvania. The first collaboration achieved a 73% decrease in the rolling average of wrong-site events over 18 months. The second collaboration experienced no wrong-site operating room procedures over more than one year

Data handling methods and target detection results for multibeam and sidescan data collected as part of the search for SwissAir Flight 111

The crash of SwissAir Flight 111, off Nova Scotia in September 1998, triggered one of the largest seabed search surveys in Canadian history. The primary search tools used were sidescan sonars (both conventional and focussed types) and multibeam sonars. The processed search data needed to be distributed on a daily basis to other elements of the fleet for precise location of divers and other optical seabed search instruments (including laser linescan and ROV video). As a result of the glacial history of the region, many natural targets, similar in gross nature to aircraft debris were present. These included widespread linear bedrock outcrop patterns together with near ubiquitous glacial erratic boulders. Because of the severely broken-up nature of the remaining aircraft debris, sidescan imaging alone was often insufficient to unambiguously identify targets. The complementary attributes of higher resolution, but poorly located, sidescan imagery together with slightly lower resolution, but excellently navigated multibeam sonar proved to be one of critical factors in the success of the search. It proved necessary to rely heavily on the regional context of the seabed (provided by the multibeam sonar bathymetry and backscatter imagery) to separate natural geomorphic targets from anomalous anthropogenic debris. In order to confidently prove or disprove a potential target, the interpreter required simultaneous access to the full resolution sidescan data in the geographic context of the multibeam framework. Specific software tools had to be adapted or developed shipboard to provide this capability. Whilst developed specifically for this application, these survey tools can provide improved processing speed and confidence as part of more general mine hunting, hydrographic, engineering or scientific surveys

Dynamic Network Construction and Updating Techniques for the Diagnoses of Acute Abdominal Pain

Computing diagnoses in domains with continuously changing data is a difficult, but essential aspect of solving many problems. To address this task, this paper describes a dynamic influence diagram (ID) construction and updating system, DYNASTY, and its application to constructing a decision-theoretic model to diagnose acute abdominal pain, a domain in which the findings evolve during the diagnostic process. For a system which evolves over time, DYNASTY constructs a parsimonious ID, and then dynamically updates the ID, rather than constructing a new network from scratch for every time interval. In addition, DYNASTY contains algorithms for testing the sensitivity of the constructed network\u27s system parameters. The main contributions of this paper are: (1) presenting an efficient temporal influence diagram technique based on parsimonious model construction; and (2) formalizing the principles underlying a diagnostic tool for acute abdominal pain which explicitly models time-varying findings

Magnetism in SQUIDs at Millikelvin Temperatures

We have characterized the temperature dependence of the flux threading dc SQUIDs cooled to millikelvin temperatures. The flux increases as 1/T as temperature is lowered; moreover, the flux change is proportional to the density of trapped vortices. The data is compatible with the thermal polarization of surface spins in the trapped fields of the vortices. In the absence of trapped flux, we observe evidence of spin-glass freezing at low temperature. These results suggest an explanation for the "universal" 1/f flux noise in SQUIDs and superconducting qubits.Comment: 4 pages, 4 figure

Towards Goal-Directed Diagnosis (Preliminary Report)

Recent research has abstracted diagnosis away from the activity needed to acquire information and to act on diagnosed disorders. In some problem domains, however, such abstraction is counter-productive and does not reflect real-life practice, which integratesdiagnostic and therapeutic activity. Trauma management is a case in point. Here, we discuss a formalization of the integrated approach taken in TraumAID, a system we have developed to serve as an artificial aide to residents and physicians dealing with multiple trauma. Among other things, the active pursuit of information raises the question of what is and what is not worth pursuing. In TraumAID 2.0, we take the view that the process of diagnosis should continue only as long as it is likely to make a difference to future actions. That view is formalized in the goal-directed diagnostic paradigm (GDD). Unlike other diagnostic paradigms, goal-directed diagnosis is first and foremost concerned with setting goals based on its conclusions. It regards the traditional construction of an explanation for the faulty behavior as secondary. In order to explicitly represent goal-directedness, the diagnostic process is viewed as search in a space of attitude-beliefs. From this, we derive a high-level algorithm that produces appropriate requests for action while searching for an explanation. A complete explanation, however, is not the criterion for terminating action. Such a criterion, we argue, is better treated in terms of goal-means tradeoffs. TraumAID\u27s architecture, in so far as it embodies this goal-directed approach, assigns to a complementary planner the resolution of such tradeoffs

Progressive Horizon Planning - Planning Exploratory-Corrective Behavior

Much planning research assumes that the goals for which one plans are known in advance. That is not true of trauma management, which involves both a search for relevant goals and reasoning about how to achieve them. TraumAID is a consultation system for the diagnosis and treatment of multiple trauma. It has been under development jointly at the University of Pennsylvania and the Medical College of Pennsylvania for the past eight years. TraumAID integrates diagnostic reasoning, planning and action. Its reasoner identifies diagnostic and therapeutic goals appropriate to the physician’s knowledge of the patient’s state, while its planner advises on beneficial actions to next perform. The physician’s lack of complete knowledge of the situation and the time limitations of emergency medicine constrain the ability of any planner to identify what would be the best thing to do. Nevertheless, TraumAID’s Progressive Horizon Planner has been designed to create a plan for patient care that is in keeping with the standards of managing trauma