Replicated Computations in a Distributed Switching Environment

Replication of computations in a distributed switching environment is studied. The first topics discussed are the requirements and the other design goals that have to be met by replicated computations in a distributed switching system. The requirements on the grade of service and availability performance objectives are largely set out in the international standards. A structured probability oriented software approach to building a kernel supporting replicated computations is suggested and the functional as well as the probability properties of the replication scheme are investigated. To aid the definition and investigation of the functional properties of the replication scheme a model of computation based on the actor model of Hewitt and Agha is defined and used. The overall replication scheme consists of a loose basic scheme, the real-time computation migration tools, here designated as warm-up algorithms, and the corrective replication tools augmenting the basic scheme. Language methods which enhance the transparency of the replication scheme are also discussed. The work has been done in connection with a redesign project of a distributed digital switching system and the results have largely been implemented in that environment

The Third NASA Goddard Conference on Mass Storage Systems and Technologies

This report contains copies of nearly all of the technical papers and viewgraphs presented at the Goddard Conference on Mass Storage Systems and Technologies held in October 1993. The conference served as an informational exchange forum for topics primarily relating to the ingestion and management of massive amounts of data and the attendant problems involved. Discussion topics include the necessary use of computers in the solution of today's infinitely complex problems, the need for greatly increased storage densities in both optical and magnetic recording media, currently popular storage media and magnetic media storage risk factors, data archiving standards including a talk on the current status of the IEEE Storage Systems Reference Model (RM). Additional topics addressed System performance, data storage system concepts, communications technologies, data distribution systems, data compression, and error detection and correction

Quality assurance of rectal cancer diagnosis and treatment - phase 3 : statistical methods to benchmark centres on a set of quality indicators

In 2004, the Belgian Section for Colorectal Surgery, a section of the Royal Belgian Society for Surgery, decided to start PROCARE (PROject on CAncer of the REctum), a multidisciplinary, profession-driven and decentralized project with as main objectives the reduction of diagnostic and therapeutic variability and improvement of outcome in patients with rectal cancer. All medical specialties involved in the care of rectal cancer established a multidisciplinary steering group in 2005. They agreed to approach the stated goal by means of treatment standardization through guidelines, implementation of these guidelines and quality assurance through registration and feedback. In 2007, the PROCARE guidelines were updated (Procare Phase I, KCE report 69). In 2008, a set of 40 process and outcome quality of care indicators (QCI) was developed and organized into 8 domains of care: general, diagnosis/staging, neoadjuvant treatment, surgery, adjuvant treatment, palliative treatment, follow-up and histopathologic examination. These QCIs were tested on the prospective PROCARE database and on an administrative (claims) database (Procare Phase II, KCE report 81). Afterwards, 4 QCIs were added by the PROCARE group. Centres have been receiving feedback from the PROCARE registry on these QCIs with a description of the distribution of the unadjusted centre-averaged observed measures and the centre’s position therein. To optimize this feedback, centres should ideally be informed of their risk-adjusted outcomes and be given some benchmarks. The PROCARE Phase III study is devoted to developing a methodology to achieve this feedback

On the performance and programming of reversible molecular computers

If the 20th century was known for the computational revolution, what will the 21st be known for? Perhaps the recent strides in the nascent fields of molecular programming and biological computation will help bring about the ‘Coming Era of Nanotechnology’ promised in Drexler’s ‘Engines of Creation’. Though there is still far to go, there is much reason for optimism. This thesis examines the underlying principles needed to realise the computational aspects of such ‘engines’ in a performant way. Its main body focusses on the ways in which thermodynamics constrains the operation and design of such systems, and it ends with the proposal of a model of computation appropriate for exploiting these constraints. These thermodynamic constraints are approached from three different directions. The first considers the maximum possible aggregate performance of a system of computers of given volume, V, with a given supply of free energy. From this perspective, reversible computing is imperative in order to circumvent the Landauer limit. A result of Frank is refined and strengthened, showing that the adiabatic regime reversible computer performance is the best possible for any computer—quantum or classical. This therefore shows a universal scaling law governing the performance of compact computers of ~V^(5/6), compared to ~V^(2/3) for conventional computers. For the case of molecular computers, it is shown how to attain this bound. The second direction extends this performance analysis to the case where individual computational particles or sub-units can interact with one another. The third extends it to interactions with shared, non-computational parts of the system. It is found that accommodating these interactions in molecular computers imposes a performance penalty that undermines the earlier scaling result. Nonetheless, scaling superior to that of irreversible computers can be preserved, and appropriate mitigations and considerations are discussed. These analyses are framed in a context of molecular computation, but where possible more general computational systems are considered. The proposed model, the א-calculus, is appropriate for programming reversible molecular computers taking into account these constraints. A variety of examples and mathematical analyses accompany it. Moreover, abstract sketches of potential molecular implementations are provided. Developing these into viable schemes suitable for experimental validation will be a focus of future work

Croatia: Integration Perspectives and Synergic Effects of European Transformation in the Countries Targeted by EU Enlargement and Neighbourhood Policies Economy

In the framework of a research project Croatia Integration Perspectives and Synergic Effects of European Transformation in the Countries Targeted by EU Enlargement and Neighbourhood Policies, this paper provides a comprehensive analysis of the state of the transformation processes in Croatia as well as its relations with the EU. Systematic study analyzes the political and economic transformation that took place in Croatia since 1990 up until today, as well as the course of its relations with the EU. The research also draws conclusions regarding the achievements of the transition process and European integration perspectives of candidate countries, potential candidate countries and countries covered by the EU’s Neighborhood Policy.Croatia, EU, Economy, enlargement, European Transformation, Integration Perspectives

MediaSync: Handbook on Multimedia Synchronization

This book provides an approachable overview of the most recent advances in the fascinating field of media synchronization (mediasync), gathering contributions from the most representative and influential experts. Understanding the challenges of this field in the current multi-sensory, multi-device, and multi-protocol world is not an easy task. The book revisits the foundations of mediasync, including theoretical frameworks and models, highlights ongoing research efforts, like hybrid broadband broadcast (HBB) delivery and users' perception modeling (i.e., Quality of Experience or QoE), and paves the way for the future (e.g., towards the deployment of multi-sensory and ultra-realistic experiences). Although many advances around mediasync have been devised and deployed, this area of research is getting renewed attention to overcome remaining challenges in the next-generation (heterogeneous and ubiquitous) media ecosystem. Given the significant advances in this research area, its current relevance and the multiple disciplines it involves, the availability of a reference book on mediasync becomes necessary. This book fills the gap in this context. In particular, it addresses key aspects and reviews the most relevant contributions within the mediasync research space, from different perspectives. Mediasync: Handbook on Multimedia Synchronization is the perfect companion for scholars and practitioners that want to acquire strong knowledge about this research area, and also approach the challenges behind ensuring the best mediated experiences, by providing the adequate synchronization between the media elements that constitute these experiences

Content-Aware Multimedia Communications

The demands for fast, economic and reliable dissemination of multimedia information are steadily growing within our society. While people and economy increasingly rely on communication technologies, engineers still struggle with their growing complexity. Complexity in multimedia communication originates from several sources. The most prominent is the unreliability of packet networks like the Internet. Recent advances in scheduling and error control mechanisms for streaming protocols have shown that the quality and robustness of multimedia delivery can be improved significantly when protocols are aware of the content they deliver. However, the proposed mechanisms require close cooperation between transport systems and application layers which increases the overall system complexity. Current approaches also require expensive metrics and focus on special encoding formats only. A general and efficient model is missing so far. This thesis presents efficient and format-independent solutions to support cross-layer coordination in system architectures. In particular, the first contribution of this work is a generic dependency model that enables transport layers to access content-specific properties of media streams, such as dependencies between data units and their importance. The second contribution is the design of a programming model for streaming communication and its implementation as a middleware architecture. The programming model hides the complexity of protocol stacks behind simple programming abstractions, but exposes cross-layer control and monitoring options to application programmers. For example, our interfaces allow programmers to choose appropriate failure semantics at design time while they can refine error protection and visibility of low-level errors at run-time. Based on some examples we show how our middleware simplifies the integration of stream-based communication into large-scale application architectures. An important result of this work is that despite cross-layer cooperation, neither application nor transport protocol designers experience an increase in complexity. Application programmers can even reuse existing streaming protocols which effectively increases system robustness.Der Bedarf unsere Gesellschaft nach kostengünstiger und zuverlässiger Kommunikation wächst stetig. Während wir uns selbst immer mehr von modernen Kommunikationstechnologien abhängig machen, müssen die Ingenieure dieser Technologien sowohl den Bedarf nach schneller Einführung neuer Produkte befriedigen als auch die wachsende Komplexität der Systeme beherrschen. Gerade die Übertragung multimedialer Inhalte wie Video und Audiodaten ist nicht trivial. Einer der prominentesten Gründe dafür ist die Unzuverlässigkeit heutiger Netzwerke, wie z.B.~dem Internet. Paketverluste und schwankende Laufzeiten können die Darstellungsqualität massiv beeinträchtigen. Wie jüngste Entwicklungen im Bereich der Streaming-Protokolle zeigen, sind jedoch Qualität und Robustheit der Übertragung effizient kontrollierbar, wenn Streamingprotokolle Informationen über den Inhalt der transportierten Daten ausnutzen. Existierende Ansätze, die den Inhalt von Multimediadatenströmen beschreiben, sind allerdings meist auf einzelne Kompressionsverfahren spezialisiert und verwenden berechnungsintensive Metriken. Das reduziert ihren praktischen Nutzen deutlich. Außerdem erfordert der Informationsaustausch eine enge Kooperation zwischen Applikationen und Transportschichten. Da allerdings die Schnittstellen aktueller Systemarchitekturen nicht darauf vorbereitet sind, müssen entweder die Schnittstellen erweitert oder alternative Architekturkonzepte geschaffen werden. Die Gefahr beider Varianten ist jedoch, dass sich die Komplexität eines Systems dadurch weiter erhöhen kann. Das zentrale Ziel dieser Dissertation ist es deshalb, schichtenübergreifende Koordination bei gleichzeitiger Reduzierung der Komplexität zu erreichen. Hier leistet die Arbeit zwei Beträge zum aktuellen Stand der Forschung. Erstens definiert sie ein universelles Modell zur Beschreibung von Inhaltsattributen, wie Wichtigkeiten und Abhängigkeitsbeziehungen innerhalb eines Datenstroms. Transportschichten können dieses Wissen zur effizienten Fehlerkontrolle verwenden. Zweitens beschreibt die Arbeit das Noja Programmiermodell für multimediale Middleware. Noja definiert Abstraktionen zur Übertragung und Kontrolle multimedialer Ströme, die die Koordination von Streamingprotokollen mit Applikationen ermöglichen. Zum Beispiel können Programmierer geeignete Fehlersemantiken und Kommunikationstopologien auswählen und den konkreten Fehlerschutz dann zur Laufzeit verfeinern und kontrolliere

Incorporating external effects in economic evaluation: The case of smoking

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The aim of this thesis is to explore methods to incorporate external effects on decision making of public health programmes in a UK setting, using smoking cessation as an example. The National Institute for Health and Clinical Excellence (NICE) methodological guidance for evaluating public health programmes is missing the incorporation of external effects. Therefore there is a need for considering their incorporation in such evaluations and to assess what are the appropiate methods to do so. Smoking cessation is an example where epidemiological evidence of external effects exists but has not generally been incorporated into economic evaluation. This thesis therefore focused in measuring the impact, in terms of costs and QALYs lost, of the incorporation of passive smoking, smoking during pregnancy and transmission of smoking behavior into economic evaluation of smoking cessation programmes previously developed to inform policy. A static Markov model is used to incorporate passive smoking and smoking during pregnancy, whereas transmisison of smoking behaviour is incorporated through a dynamic model. The findings show that some external effects can be incorporated without a system dynamic model, when this does occur, a static Markov model may be used to account for external effects in economic evaluation. Sometimes, to incorporate external effects, the model needs a change of population. Because smoking cessation interventions are generally highly cost-effective, the incorporation of external effects does not appear to change policy decisions, but there is a clear impact on the magnitude of the ICER. Passive smoking and smoking during pregnancy have higher impact in terms of costs and QALYs lost than transmission of smoking behaviour. Our discussion considers the validity of the methods used; how much the decision making process would be affected considering or not external effects on economic evaluation of smoking cessation interventions; and other valuation approaches for external effects, such as contingent valuation