Aspects of Information Flow

Along with our colleagues at the Oregon Graduate Institute and Georgia Institute of Technology, we have recently been experimenting with real-rate systems, that is, systems that are required to move data from one place to another at defined rates, such as 30 items per second. Audio conferencing or streaming video systems are typical: they are required to deliver video or audio frames from a source (a server or file system) in one place to a sink (a display or a sound generator) in another; the frames must arrive periodically, with constrained latency and jitter. We have successfully built such systems (for example, see reference [Walpole 1997]), but they are not simple to design or construct. Our current research seeks to capture our knowledge of this domain into an information flow framework, called InfoPipes. The goal of Infopipes is to make the task of building a system that moves data from one part of the Internet to another as simple as connecting pre-defined components such as buffers, pipes, filters and meters. The latency, jitter and data-rate properties of the resulting pipeline should follow by calculation from the properties of the components

Health informatics in UK Medical Education: an online survey of current practice

OBJECTIVE: Health informatics has growing importance in clinical practice with successive General Medical Council recommendations. However, prior data suggest that undergraduate medical education largely neglects this area. An up-to-date, UK-wide view of health informatics training in medical schools is required. DESIGN: An online survey was developed using current guidance and recommendations of UK professional bodies. PARTICIPANTS AND SETTING: Senior academic staff and health informatics educators at all 34 UK medical schools were invited to complete the survey. MAIN OUTCOME AND MEASURES: Quantitative and qualitative data regarding health informatics in the undergraduate medical curriculum. RESULTS: A total of 26/34 (76%) of UK medical schools responded and 23 provided full information. Aspects most frequently mentioned were literature searching and research governance. Seventeen per cent of respondents felt there was little or no HI training, although clinical record keeping was addressed by all medical schools. Pedagogies used to teach health informatics were self-directed learning (78%) to lecture based (70%), seminars (70%), informal teaching in clinical settings (57%) and problem-based learning (22%). Health informatics was usually integrated vertically and horizontally across the curriculum (76%). Assessment and updates of the health informatics curriculum are limited (57 and 41%, respectively). Thirty-two per cent of respondents reported a low level of confidence among students to use health informatics as doctors. In the most up-to-date survey of health informatics teaching in UK medical schools, there are three major findings. First, the proportion of health informatics in the medical undergraduate curriculum is low. Second, there was variation in content, pedagogy and timing across medical schools. Third, health informatics is rarely assessed and course content is not regularly updated. CONCLUSIONS: There is a role for national guidelines and further research in this area of the curriculum which is rapidly gaining in prominence

The ecomics of ecosystems and biodiversity: scoping the scale

The G8 decided in March 2007 to initiate a “Review on the economics of biodiversity loss”, in the so called Potsdam Initiative: 'In a global study we will initiate the process of analysing the global economic benefit of biological diversity, the costs of the loss of biodiversity and the failure to take protective measures versus the costs of effective conservation. The study is being supported by the European Commission (together with the European Environmental Agency and in cooperation with the German Government. “The objective of the current study is to provide a coherent overview of existing scientific knowledge upon which to base the economics of the Review, and to propose a coherent global programme of scientific work, both for Phase 2 (consolidation) and to enable more robust future iterations of the Review beyond 2010.

Infopipes—an Abstraction for Information Flow

Building Object-Oriented Distributed Systems has been facilitated by Remote Message Sending (RMS) systems like Java RMI and implementations of CORBA. However, RMS systems are designed to support request/response interactions. Streaming applications, in contrast, are characterized by high-bandwidth, long-duration communication with stringent performance requirements. Examples of streaming applications include video-on-demand, teleconferencing, on-line education, and environmental observation. These applications transfer huge amounts of data and focus on distributed information flow rather than request/response. To simplify the task of building distributed streaming applications, we propose a new abstraction for information flow—Infopipes. Using Infopipes, information flow becomes the heart of the system, not an auxiliary mechanism that is hidden away. Systems are built by connecting pre-defined component Infopipes such as sources, sinks, buffers, filters, broadcasting pipes, and multiplexing pipes. An Infopipe has a data interface that pulls information items from the upstream Infopipes, or pushes them into the downstream Infopipes, or both. An Infopipe also has a control interface that dynamically monitors and controls the properties of the Infopipe, and hence the properties of the information flowing through it. We intend to provide property-preserving composition of Infopipes, so that the properties of the whole pipeline can be calculated from the properties of the component Infopipes in it. Quality of Service (QoS) requirements then can be analyzed and understood system-wide. In Section 2 we discuss related technologies. In Section 3 we describe the concepts of Infopipes. We report our work on an Infopipe prototype in Section 4. Section 5 summarizes the features of Infopipes and lists some open questions

The evolution of the Pine Creek Geosyncline and its relation to the structural framework of north-western Australia

This Thesis presents an account of the geology of the Lower Proterozoic rocks which occupy the Pine Creek Geosyncline, and attempts to trace the evolution of the geosyncline by a reconstruction of the sequence of deposition of the sediments; by relating different facies assemblages to structural units developed in the geosynolinal tract; and by a brief consideration of the igneous rocks, which, together with the sediments, make up the geosynclinal pile. The geosyncline is discussed as a unit within the structural framework of North-western Australia, which, for the purpose of this Thesis, is taken as the area shown on Plate 6. The thesis is divided into three parts: Part 1 is descriptive and deals with the stratigraphy of the Lower Proterozoic rocks of the geosyncline, with brief descriptions of the igneous rocks. Rock units of other ages in the area are noted but not described. Part 2 is interpretative and traces the evolution of the geosyncline. Some repetition of material presented in the first section has been found necessary here in order to maintain the continuity of the discussion. Part 3 offers a new reconstruction of the Precambrian framework of North-western Australia in order to explain further the tectonic style and sedimentation pattern of the Pine Creek Geosyncline

Unbound states of 32Cl and the 31S(p,\gamma)32Cl reaction rate

The 31S(p,\gamma)32Cl reaction is expected to provide the dominant break-out path from the SiP cycle in novae and is important for understanding enrichments of sulfur observed in some nova ejecta. We studied the 32S(3He,t)32Cl charge-exchange reaction to determine properties of proton-unbound levels in 32Cl that have previously contributed significant uncertainties to the 31S(p,\gamma)32Cl reaction rate. Measured triton magnetic rigidities were used to determine excitation energies in 32Cl. Proton-branching ratios were obtained by detecting decay protons from unbound 32Cl states in coincidence with tritons. An improved 31S(p,\gamma)32Cl reaction rate was calculated including robust statistical and systematic uncertainties

Customizable Operating Systems

A customizable operating system is one that can adapt to improve its functionality or performance. The need for customizable and application-specific operating systems has been recognized for many years, but they have yet to appear in the commercial market. This paper explores the notion of operating system customizability and examines the limits of existing approaches. The paper begins by surveying system structuring approaches for the safe and efficient execution of customizable operating systems. Then it discusses the burden that existing approaches impose on application software, and explores techniques for reducing this burden. Finally, support for customizability in the Synthetix project is described and illustrated through two examples: a dynamically specialized file system read call, and an adaptive Internet-based MPEG video player

Location of Plastic Hinges in Axially Loaded Steel Members

New Zealand and Australian steel structure design standards contain equations to encourage yielding at the ends of steel members rather than along their lengths. This paper evaluates the accuracy of these equations using a commercially available computer program as well as an analytical procedure. The analytical procedure considers non-linear geometric effects and material effects of the member stiffness by considering stability functions in conjunction with residual stress effects. New equations to prevent yielding away from the member ends, which are less conservative than the current code equations, are developed. Simplifications of these equations being considered for adoption into the New Zealand steel structure design standard are described