15 research outputs found

    Proceedings Work-In-Progress Session of the 13th Real-Time and Embedded Technology and Applications Symposium

    Get PDF
    The Work-In-Progress session of the 13th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS\u2707) presents papers describing contributions both to state of the art and state of the practice in the broad field of real-time and embedded systems. The 17 accepted papers were selected from 19 submissions. This proceedings is also available as Washington University in St. Louis Technical Report WUCSE-2007-17, at http://www.cse.seas.wustl.edu/Research/FileDownload.asp?733. Special thanks go to the General Chairs – Steve Goddard and Steve Liu and Program Chairs - Scott Brandt and Frank Mueller for their support and guidance

    Application of object-orientation to HDL-based designs

    Get PDF
    The increase in the scale of VLSI circuits over the last two decades has been of great importance to the development process. To cope with this ever­growing design complexity. new development techniques and methodologies have been researched and applied. The early 90's have witnessed the uptake of a new kind of design methodology based on Hardware Description Languages (HDL). This methodology has helped to master the possibilities inherent in our ability to manufacture ever-larger designs. However. while HDL based design methodology is sufficient to address today's standard ASIC sizes, it reaches its limits when considering tomorrow's design scales. Already. RISC processor chip descriptions can contain tens of thousands of HDLlines. Object-Oriented design methodology has recently had a considerable Impact in the software design community as it is tightly coupled with the handling of complex systems. Object-Orientation concentrates on data rather than functions since. throughout the design process. data are more stable than functions. Methodologies for both hardware and software have been introduced through the application of HDLs to hardware design. Common design constructs and principles that have proved successful in software language development should therefore be considered in order to assess their suitability for HDLs based designs. A new methodology was created to emphasise on encapsulation. abstraction and classification of designs. using standard VHDL constructs. This achieves higher levels of modelling along with an Improved reusability through design inheritance. The development of extended semantics for integrating Object-Orientation in the VHDL language is described. Comparisons are made between the modelling abilities of the proposed extension and other competing proposals. A UNIX based Object-Oriented to standard VHDL pre-processor is described along with translation techniques and their issues related to synthesis and simulation. This tool permitted validation of the new design methodology by application to existing design problems

    Fault-tolerant computation in semigroups and semirings

    Get PDF
    "May 1995."Includes bibliographical references (p. 82-84).Supported in part by the Department of the Navy, Office of the Chief of Naval Research as part of the Advanced Research Projects Agency's RASSP program. N00014-93-1-0686Christoforos N. Hadjicostis

    An Adaptive Framework for Improving the Effectiveness of Virtual Enterprises in the Supply Chain

    Get PDF
    This thesis describes a research project that develops an adaptive framework for improving the effectiveness of virtual enterprises in the supply chains in Mongolia. The research takes empirical and quantitative approach to study the phenomenon of virtual enterprises. Based on a literature review, the factors that influence organisations to join in virtual enterprises are studied by a higher-order factor analysis. As a result, agility is identified as one of the main benefits organisations can gain by joining a virtual enterprise temporarily and changes in business performance are conceived as the measures of effectiveness. Next, a taxonomy of enterprises is developed with five distinguishing clusters that achieve differing levels of agility and business performance. This study suggests that enterprises that are monitoring changes in their business environment take most advantage of agility and achieve the best levels of performance. These findings then allow an adaptive framework based on common reference architectures to be developed as a main contribution of this study. The framework includes a breeding environment as a ‘pool’ of prepared enterprises with the ability to form temporary collaborations to react responsively, rapidly and effectively to the fast-changing opportunities. A structural equation model was used to examine the model fit with the supporting hypotheses, based on the observed data. Then, a powerful clustered expectation maximisation algorithm was applied to the analysis of the grouped enterprises. Finally, a simulation-based case study was conducted to validate the developed framework. The results provide rich empirical evidence of the beneficial impact of virtual enterprises on agile supply chains. The research provides rich empirical evidence of the beneficial impact of virtual enterprises on agile supply chains. It also provides theoretical and managerial insights that can be used to strengthen the drivers, enablers and capabilities that enhance the effectiveness of virtual enterprises collaboration in agile supply chains that can be translated to a global context. These are major contributions the ‘body of knowledge’ in themselves, but the research also adds usefully to the study of applied research methodologies in the area

    SoCRocket - A flexible and extensible Virtual Platform for the development of robust Embedded Systems

    Get PDF
    Der Schwerpunkt dieser Arbeit liegt in der Erhöhung des Abstraktionsniveaus im Entwurfsprozess, speziell dem Entwurf von Systemen auf Basis von Virtuellen Plattformen (VPs), Transaction-Level-Modellierung (TLM) und SystemC. Es wird eine ganzheitliche Methode vorgestellt, mit der komplexe eingebettete Systeme effizient modelliert werden können. Ergebnis ist eine der RTL-Synthese nahezu gleichgestellte Genauigkeit bei wesentlich höherer FlexibilitĂ€t und Simulationsgeschwindigkeit. Das SoCRocket-System orientiert sich dazu an existierenden Standards und stellt Methoden zu deren effizientem Einsatz zur Verbesserung von Simulationsgeschwindigkeit und Simulationsgenauigkeit vor. So wird unter anderem gezeigt, wie moderne Multi-Kanal-Protokolle mit Split-Transfers durch Ausgleich des Intertransaktions-Timings ohne die EinfĂŒhrung zusĂ€tzlicher Protokollphasen zeitlich genau modelliert werden können. StandardisierungslĂŒcken in den Bereichen Speichermodellierung und Systemkonfiguration werden durch standardoffene Lösungen geschlossen. DarĂŒber hinaus wird neue Infrastruktur zur Modellierung von Signalkommunikation auf Transaktionsebene, der Verifikation von Komponenten und der Modellierung des Energieverbrauchs vorgestellt. Zur Demonstration wurden die Kernkomponenten einer im europĂ€ischen Raumfahrtsektor maßgeblichen Hardwarebibliothek modelliert. Alle Komponenten wurden zunĂ€chst in Unit-Tests verifiziert und anschließend in einem Systemprototypen integriert. Zur Verifikation der Funktion, sowie Bestimmung von Simulationsgeschwindigkeit und zeitlicher Genauigkeit, wurde dieser fĂŒr unterschiedliche Abstraktionsstufen konfiguriert und mit einem in VHDL beschriebenen RISC-Referenzentwurf (LEON3MP) verglichen. Das System mit losem Timing (LT) und blockierender Kommunikation ist im Durchschnitt 561-mal schneller als die RTL-Referenz und weist eine durchschnittliche Timing-Abweichung von 7,04% auf. Das System mit nĂ€herungsweise akkuratem Timing (AT) und nicht-blockierender Kommunikation ist 335-mal schneller. Die durchschnittliche Timing-Abweichung betrĂ€gt hier nur noch 3,03%, was einer Standardabweichung von 0.033 und damit einer sehr hohen statistischen Sicherheit entspricht. Die verschiedenen Abstraktionsniveaus können zur Realisierung mehrstufiger Architekturexplorationen eingesetzt werden. Dies wird am Beispiel einer hyperspektralen Bildkompression verdeutlicht.The focus of this work is raising the abstraction level in the development process, especially for the design of systems based on Virtual Platforms (VPs), Transaction Level Modeling (TLM), and SystemC. A holistic method for efficient modeling of complex embedded systems is presented. Results are accuracies close to RTL synthesis but at much higher flexibility, and simulation performance. The SoCRocket system integrates existing standards and introduces new methods for improvement of simulation performance and accuracy. It is shown, amongst others, how modern multi-channel protocols with split transfers can be accurately modeled by compensating inter-transaction timing without introducing additional protocol phases. Standardization gaps in the area of memory modeling and system configuration are closed by standard-open solutions. Furthermore, new infrastructure for modeling signal communication on transaction level, verification of components, and estimating power consumption are presented. All components have been verified in unit tests and were subsequently integrated in a system prototype. For functional verification, as well as measurement of simulation performance and accuracy, the prototype was configured for different abstractions and compared to a VHDL-based RISC reference design (LEON3MP). The loosely-timed platform prototype with blocking communication (LT) is in average 561 times faster than the RTL reference and shows an average timing deviation of 7,04%. The approximately-timed system (AT) with non-blocking communication is 335 times faster. Here, the timing deviation is only 3,03 %, corresponding to a standard deviation of 0.033, proving a very high statistic certainty. The system’s various abstraction levels can be exploited by a multi-stage architecture exploration. This is demonstrated by the example of a hyperspectral image compression

    A Cultural Heritage Management Methodology for Assessing the Vulnerabilities of Archaeological Sites to Predicted Climate Change Focuing on Ireland\u27s Two World Heritage Sites

    Get PDF
    The affect climate change will have on cultural heritage preservation poses a global challenge and is being addressed by international organisations such as UNESCO and ICOMOS. The aim of this doctoral research is to assist heritage managers in understanding the implications of climate change for the sites in their care. It addresses the question of how to approach the assessment and measurement of climate change impacts on cultural heritage. The potential future effects of climate change on cultural heritage in temperate climates are discussed and current international practice in the management of climate change impacts on cultural heritage is investigated. The results reveal several issues currently of concern amongst practitioners; namely ‘what’ to monitor, ‘how’ to monitor and how to interpret results when dealing with the highly complex and long-term issue of climate change impacts. A Vulnerability Framework for site based evaluations is defined and adapted specifically for cultural heritage. This six step method relies on expert judgement and stakeholder involvement; it is a place based approach studying the coupled ‘human-environment system’. The Framework is illustrated through the assessment of the vulnerability of Ireland’s World Heritage Sites, Skellig Michael and BrĂș na BĂłinne, to the impacts of projected climate change up to 2100. The results suggest that the projected alterations in rainfall will be the most problematic climate change factor for both sites. Climate change indicators developed as part of the Vulnerability Framework are proposed as a solution to the problem of longterm monitoring. The development of a general Toolbox of Indicators is accompanied by the design and pilot trial of a Legacy Indicator Tool (LegIT). This tool, for tracking the surface weathering of stone and related materials, can be tailored to the needs of individual heritage sites and is currently being piloted at five monuments in Ireland, including the two case studies. Phase One – Initial Vulnerability Assessment Cycle. Phase Two – Subsequent ongoing Adaptation and Review Cycle. Cultural Heritage Management Model developed for the assessment of, and adaptation to, climate change impacts In this research transferable methodologies for the site level assessment and measurement of climate change vulnerabilities are developed and applied in practice. The Vulnerability Framework, Impacts Matrix, Toolbox of Indicators and Legacy Indicator Tool (LegIT) are original and transferable outputs. They will aid decision makers with planning and prioritisation for the case study sites and provide a management model that has the potential to facilitate assessments at other sites in Ireland and internationally
    corecore