No description available.

No description available.

Thesis (PhD)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: The engineering of dependable real-time systems for mission critical applications is a resource intensive and error prone process. Achieving dependability requires a general consensus on the correctness of a system with regard to its intended function. For a consensus to be achieved, the properties of the system must be well understood which, in turn, requires consensus on a rigorously defined computational architecture. There is currently no single agreed upon computational architecture at the application level which can serve as a common denominator for the design and implementation of real-time systems. It is the thesis of this dissertation that a rigorous computational architecture, applicable from design to implementation, enables engineers to better understand software for real-time systems. To substantiate this claim, the real-time data flow architecture RDF with its notation allowing the description of complete systems from design to implementation will be explored. Four distinct research areas for improving the engineering process of real-time systems are dealt with in the dissertation: 1) the development of an architecture for real-time systems being suitable for design and implementation in software and hardware, 2) the consolidation of a number of graphical languages into a graphical notation for functional specification, design and construction of real-time systems, 3) the development of a simple processor architecture for the execution of real-time applications, and 4) and the evaluation of the architecture in the framework of a microsatellite case study. In particular, the following original contributions are made: 1) the firing semantics of data flow systems are expanded to include disjunctive firing semantics in a novel way in addition to the classical conjunctive firing semantics, 2) the inherent real-time data flow property, Le. that a receiving task must be ready to receive the next incoming message when it is sent, is extended to the synchronous data flow model, 3) a notation for describing all properties of real-time systems is defined 'with the real-time data flow language RDF as base language, 4) two hardware processor architectures are introduced that offer one-to-one correspondence between design and implementation and, thus, reduce the semantic gap between design language and program execution, and 5) the class of systems that can be modelled with data flow architectures is shown to include control systems and data flow systems. The language set and processor architecture were applied to certain aspects of the SUNSAT microsatellite project. / AFRIKAANSE OPSOMMING:Die skep van betroubare intydsestelsels vir missie kritiese toepassings is 'n proses wat baie hulpbronne verg en waarin maklik 'n fout gemaak kan word. Om 'n betroubare stelsel te skep vereis 'n konsensus oor die korrektheid van 'n stelsel, wat bereik word wanneer die eienskappe van die stelsel goed verstaan word. Dit vereis op sy beurt weer 'n konsensus oor 'n goed gedefinieerde berekenings argitektuur. Daar is tans geen enkel ooreengekome berekenings argitektuur op die toepassingsvlak wat kan dien as 'n gemeenskaplike voertuig vir die ontwerp en implementering van intydsestelsels nie. Dit is die hipotese van die proefskrif dat 'n berekenings argitektuur met 'n streng basis, wat toegepas kan word vanaf ontwerp tot implementering, ingenieurs in staat sal stel om intydsestelsels beter te kan verstaan. Die hipotese word ondersoek deur die intydse datavloei argitektuur, RDF, te gebruik om 'n stelsel vanaf ontwerp tot implementering te beskryf. Daar is vier spesifieke navorsings areas ter verbetering van die ingenieurswese proses vir intydsestelsels, wat in die proefskrif aangespreek word: 1) die ontwikkelling van 'n argitektuur vir intydsestelsels wat geskik is vir die ontwerp en implementering in programmatuur en apparatuur, 2) . die konsolidering van 'n aantal grafiese tale in 'n grafiese notasie vir die funksionele spesifikasie, ontwerp en implementering van intydsestelsels, 3) die ontwikkelling van 'n eenvoudige verwerker argitektuur vir die uitvoering van intydse toepassings en 4) die evaluering van die argitektuur in die konteks van 'n mikrosatelliet gevallestudie. Die volgende oorspronklike bydraes word gemaak: 1) die sneller voorwaardes vir datavloei stelsels word uitgebrei met 'n disjunktiewe patroon saam met die tradisionele konjunktiewe patroon, 2) die inherente intydse datavloei eienskap, n.l. dat'n taak wat boodskappe ontvang, alle verwerking wat met 'n vorige boodskap gepaard gegaan het moet afhandel, voordat 'n volgende boodskap ontvang word, word uitgebrei na die sinkrone datavloei model, 3) 'n notasie om al die eienskappe van 'n intydsestelsel te beskryf word gedefinieer met RDF as die basis taal, 4) twee apparatuur verwerker argitekture word beskryf wat 'n een-tot-een kartering aanbied tussen die ontwerp en die implementering, en wat gevolglik die semantiese gaping verklein tussen ontwerpstaal en die uitvoeringsargitektuur en 5) die klasse van stelsels wat gemodelleer kan word met RDF sluit beheerstelsels en datavloeistelsels in. Die grafiese notasie en verwerker argitektuur was toegepas op sekere aspekte van die SUNSAT mikrosatelliet projek.

Mineral processing plan ts, such as LONMIN's Eastern Platinum B-stream, typically have few on-line measurements, and key measures of performance such as grade only become available after samples have been analysed in the laboratory. More immediate feedback from a dynamic observer model promises enhanced understanding of the process, and facilitates prompt corrective actions, whether in open or closed loop . Such plant s easily enter sub-optimal modes such as large , uselessly re-circulating loads as the feed conditions change. Interpretation of such modes from key combinations of the variables deduced by an observer model , using a type of expert system, would add another level of intelligence to benefit operation. The aim of this thesis was to develop and implement a dynamic observer model of the LONMIN Eastern Platinum B-Stream into one of the existing control platforms available at the plant , known as PlantStar®, developed by MINTEK. The solution of the system of differential and algebraic equations resulting from this type of flowsheet modelling is based on an extended Kalman filter, which is able to dynamically reconcile any measurements which are presented to it, in real time. These measurement selections may also vary in real time, which provides flexibility of the model solution and the model 's uses. PlantStar passes the measurements that are available at the plant, to the dynamic observer model through a "plugin" module, which has been developed to incorporate the observer model and utilise the PlantStar control platform. In an on-line situation, the model will track the plant's behaviour and continuously update its position in real-time to ensure it follows the plant closely. This model would then be able to run simulations of the plant in parallel and could be used as a training facility for new operators, while in a real-time situation it could provide estimates of unmeasurable variables throughout the plant. An example of some of these variables are the flotation rate constants of minerals throughout the plant, which can be estimated in real time by the extended Kalman filter. The model could also be used to predict future plant conditions based on the current plant state , allowing for case scenarios to be performed without affecting the actual plant's performance. Once the dynamic observer model and "plugin" module were completed, case scenario simulations were performed using a measured data set from the plant as a starting point because real-time data were unavailable as the model was developed off-site . / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2004.

Beneath the facade of the applications code of a well-designed real-time embedded system lies intrinsic firmware that facilitates a fast and effective means of detecting and diagnosing inevitable hardware failures. These failures can encumber the availability of a system, and, consequently, an identification of the source of the malfunction is needed. It is shown that the number of possible origins of all manner of failures is immense. As a result, fault models are contrived to encompass prevalent hardware faults. Furthermore, the complexity is reduced by determining syndromes for particular circuitry and applying test vectors at a functional block level. Testing phases and philosophies together with standardisation policies are defined to ensure the compliance of system designers to the underlying principles of evaluating system integrity. The three testing phases of power-on self tests at system start up, on-line health monitoring and off-line diagnostics are designed to ensure that the inherent test firmware remains inconspicuous during normal applications. The prominence of the code is, however, apparent on the detection or diagnosis of a hardware failure. The authenticity of the theoretical models, standardisation policies and built-in test philosophies are illustrated by means of their application to an intricate real-time system. The architecture and the software design implementing the idealogies are described extensively. Standardisation policies, enhanced by the proposition of generic tests for common core components, are advocated at all hierarchical levels. The presentation of the integration of the hardware and software are aimed at portraying the moderately complex nature of the task of generating a set of built-in tests for a real-time embedded system. In spite of generic policies, the intricacies of the architecture are found to have a direct influence on software design decisions. It is thus concluded that the diagnostic objectives of the user requirements specification be lucidly expressed by both operational and maintenance personnel for all testing phases. Disparity may exist between the system designer and the end user in the understanding of the requirements specification defining the objectives of the diagnosis. It is thus essential for complete collaboration between the two parties throughout the development life cycle, but especially during the preliminary design phase. Thereafter, the designer would be able to decide on the sophistication of the system testing capabilities. / Thesis (M.Sc.)-University of Natal, Durban, 1991.

by Leung, Brain Shui-kei, Ng, Timmy Kwok-wai. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves 72-73. / ABSTRACT --- p.ii / TABLE OF CONTENTS --- p.iii / LIST OF ILLUSTRATIONS --- p.vi / LIST OF TABLES --- p.vii / ACKNOWLEDGEMENTS --- p.viii / Chapter / Chapter I. --- INTRODUCTION --- p.1 / Research Methodology --- p.4 / Chapter II. --- FACTORY-FLOOR COMPUTERIZATION OF ELECTRONICS MANUFACTURING INDUSTRY IN HONG KONG --- p.5 / An Overview of the Worldwide Electronics Manufacturing Industry --- p.5 / Electronics Manufacturing Industry in Hong Kong --- p.11 / Production Control Problems in Electronics Manufacturing Firms in Hong Kong --- p.13 / The Survey --- p.15 / The Solution: On-Line Real-Time Information System --- p.24 / Chapter III. --- A STUDY OF THE APPLICABILITY OF THE SUGGESTED ON-LINE REAL-TIME INFORMATION SYSTEM TO A MEDIUM SIZED ELECTRONICS MANUFACTURING FIRM IN HONG KONG / The Company --- p.29 / A Study of the Existing Production Controlling System --- p.30 / Problems with the Existing Production Controlling System --- p.31 / """OLRTIS""" --- p.35 / The Design of OLRTIS --- p.36 / Implementation of the Proposed OLRTIS --- p.47 / Cost / Benefits Analysis --- p.49 / Chapter IV. --- PRACTICAL CONSIDERATION --- p.56 / Top Management Attitude --- p.56 / Training of Staff and Workers --- p.57 / Acceptance/Resistance of the New System --- p.57 / "Garbage In, Garbage Out" --- p.59 / Impact of the New System on Management Organization --- p.59 / Human Resources --- p.60 / Chapter V. --- CONCLUSION --- p.61 / APPENDIXES --- p.63 / BIBLIOGRAPHY --- p.72

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Sudhindra Nath Mishra. / M.S.

Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaf 125. / by Avram K. Tetewsky. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 177-181. / by Elazer Reuven Edelman. / M.S.

University of Macau / Faculty of Science and Technology / Department of Computer and Information Science