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Software Engineering for Real Time Systems, 1991., Third International Conference on

Date 16-18 Sep 1991

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Displaying Results 1 - 25 of 49
  • Modelling real-time constraints

    Publication Year: 1991 , Page(s): 164 - 169
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (492 KB)  

    The objective of the work described is to provide a software tool to assist real-time system specifiers and designers to predict, at an early stage of the development process, the timing behaviour of the system developed. The tool (simulation of real-time systems (SRT)) is used to model the timing aspects of a real-time system and then simulate the system to predict its behaviour View full abstract»

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  • Adaptive control strategy for a water supply system

    Publication Year: 1991 , Page(s): 125 - 128
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (180 KB)  

    A description is given of the performance evaluation of an adaptive water supply control system using a personal computer PC. In order to have the plant dynamics identified in the shortest possible time, the adaptive infinite impulse response filter is formulated to represent the system dynamics. A real time recursive least squares algorithm incorporated with U-D factorization is adopted for the purpose of parameter identification. This algorithm possess significant properties in numerical stability and fast execution in arithmetic computation on the PC even without the co-processor. These are considered to be the advantages for the real time control system. The results obtained from the self-tuning control scheme with considerations for software implementation are presented View full abstract»

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  • Specification of real time control systems by means of sequential function charts

    Publication Year: 1991 , Page(s): 57 - 62
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    Very many specification techniques have been proposed for real time control systems, each with its own advantages and disadvantages. This paper considers the use of one of these techniques-sequential function charts (SFCs). SFCs are not new-GRAFCET, a standard for such charts, was presented in 1982-but until recently they were not widely known. This has now changed and the technique has received considerable coverage in the technical literature. In addition, several control system manufacturers have adopted SFCs as a programming language. The paper begins with a brief survey of specification techniques for real time control systems; it moves on to trace the origins of SFCs and then describes them in some detail. Finally, the practical production of SFCs is discussed and the need for an SFC diagram editor is identified. Current options in this field are presented View full abstract»

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  • Symbolic Occam

    Publication Year: 1991 , Page(s): 170 - 175
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (436 KB)  

    Occam is a fine grain process based programming language from the concurrent programming stable. Occam is minimal and efficient on transputers because of the hardware support for process scheduling and synchronization the hardware provides. Yet, Occam has been described as concurrent Fortran. Like Fortran, Occam is not ideally suited for symbolic, knowledge based applications. The language is inflexible, it does not support recursion, abstract data types, dynamic data structures and dynamic process creation. Occam code is not a first class object. As a result, the language is not well adapted to advanced AI programming techniques such as pattern matching, metaprogramming, partial evaluation and abstract interpretation View full abstract»

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  • Securing Ada systems

    Publication Year: 1991 , Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (252 KB)  

    This paper explains how the security assurance of an Ada real time embedded software system may be improved, and shows how this may have benefits for safety critical systems. The paper shows how Ada itself provides many of the features required for secure and safety critical systems. It describes a potential flaw in the architecture of an Ada system, which renders it insecure. The paper proposes a solution to the problem which makes use of virtual memory management enforced by hardware View full abstract»

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  • Validation methods using formal techniques

    Publication Year: 1991 , Page(s): 244 - 249
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (372 KB)  

    The need for reliable software has rapidly overtaken the ability to produce it. In control applications, particularly disastrous results may arise from errors. For many years computer scientists have been developing languages and techniques to clarify the structure of programs through establishing a sound mathematical foundation. The techniques included under the general umbrella of formal methods have been introduced especially to put the design phase of program onto an analytical basis. The authors examine their application in control systems, and especially their applicability in verifying and validating control software. The context of the article is a programme of research in developing validation techniques in control using formal methodologies. The author examines: application areas and benefits for industrial control; establishment of control software integrity; and examples of formal methods in control systems View full abstract»

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  • A handwritten Arabic character recognition technique for machine reader

    Publication Year: 1991 , Page(s): 212 - 216
    Cited by:  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (292 KB)  

    A technique for real-time recognition of unconstrained Arabic characters is presented. The proposed technique does not require any constraints of the character forms other than limiting them to a reasonable size and orientation. Structural features, which are more suitable for handwritten character recognition, are selected. Structural features that are independent of the writer style, which are called stable features, use a list of integer values (vector) to describe the character. On the other hand CHAIN CODE is used for other structural features (decisive) that are suitable for more variation of the writer style. A suitable clustering technique is chosen to accomplish the classifier procedure. The algorithm can be extended to cursive words after introducing the additional segmentation stage View full abstract»

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  • A methodology for real-time database system construction

    Publication Year: 1991 , Page(s): 233 - 238
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (424 KB)  

    A description is given of some research into well specified real-time database systems which permit analysis of the data access requirements of transactions before run-time. This enables one to do all concurrency control at system build time. Moving the concurrency control away from the run-time environment allows deterministic hard real-time scheduling of database transactions in the real-time system. A complete real-time system design and implementation methodology based on this work is presented View full abstract»

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  • A rendezvous with multitasking multiprocessors

    Publication Year: 1991 , Page(s): 129 - 134
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    Controlling process plants using computers has always had spectacular failures as well as successes. A modern distributed control system (DCS) is very powerful, incorporating multitasking multiprocessors. However, unless this power is controlled, severe technical difficulties frequently arise, causing over spending and lateness. Multitasking and multiprocessing environments allow a number of application programmes to be active simultaneously. Academics have identified and analysed the problems of interfacing application programmes operating in these environments. A number of standard solutions, which co-ordinate both the information exchange and operation of the programmes, are now widely accepted. Unfortunately these have not yet been incorporated into distributed control systems, instead only limited lower level facilities are provided. However, the application programmer can implement these solutions using what facilities are provided. The author explains how this may be achieved and outlines the benefits of doing so View full abstract»

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  • Reusing temporal properties of real-time software

    Publication Year: 1991 , Page(s): 7 - 15
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (540 KB)  

    This paper is concerned with the deterministic prediction and the reuse of temporal properties of higher order language real-time applications. It proposes a method to draw out, save, instantiate to specific hard/soft environments and finally to reuse temporal properties of software applications. The conceptual organization of a tool to support such a proposal is shown View full abstract»

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  • Performance evaluation of movable head disk schedules

    Publication Year: 1991 , Page(s): 250 - 253
    Cited by:  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    Several disk scheduling techniques have been suggested. It seems clear that the choice of an algorithm can make a significant difference in computer system performance, but which is best is still an open question. Therefore, the main contribution of the article is the detailed computational experience of three well-known schedulers, to evaluate their performances. The aim of the evaluation is to help those responsible for system operations in assessing the possibilities for improving disk performance. Finally, it is to help to choose the best scheduler suitable for a specific system with its load conditions View full abstract»

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  • Third International Conference on Software Engineering for Real Time Systems (Conf. Publ. No.344)

    Publication Year: 1991
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (48 KB)  

    The following topics were dealt with: formal methods and safety critical software; specification for real-time systems; networks; user environments; real time control systems; automatic manufacture and robotics; real time plant control; concurrent systems; and knowledge based systems for real time systems View full abstract»

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  • A pragmatic approach to low-cost, real-time, environment monitoring and prediction

    Publication Year: 1991 , Page(s): 73 - 78
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    There are several areas of environmental monitoring, prediction and control where it is desirable to achieve a real-time response using low-cost equipment. For example, the ability to obtain rapid access to weather information for agricultural and numerous other purposes; or to atmospheric pollution information in environment monitoring; or to river water level information for flooding alerts; or to water usage information for drought avoidance; could make a dramatic difference to the way of life and economy of many people, especially those who live in remote, rural areas. In many circumstances a system providing this environmental information must necessarily supplement global or large-scale data with local data to provide an effective localised facility. For example, hazardous environmental phenomena, perhaps leading to destruction of life and property, are often confined to a small-sized locality. This paper reports research which suggests that if nonphysical, heuristic, algorithms are acceptable, then a pragmatic solution may be realised using low-cost PC-based systems View full abstract»

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  • The accuracy of interrupt driven time measurements

    Publication Year: 1991 , Page(s): 217 - 220
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (212 KB)  

    In a number of microprocessor-based real time control and instrumentation systems interrupt service routines are used to record the time at which an event occurs. There are several applications of this technique. For example, if hardware is provided so that a voltage waveform of interest generates an interrupt once each cycle and an interrupt service routine is used to record the times at which these interrupts occur, the time difference between successive interrupts can be used to measure the period or frequency, of the voltage waveform. An examination is made of the accuracy of interrupt driven time measurements, and in particular of the accuracy of measurement of the time difference between successive interrupts. It is found that the primary source of error in this measurement arises from the way in which a microprocessor responds to interrupts. For a given microprocessor running a real time control program, if the probabilities of the occurrence of instructions of different length is known, it is possible to calculate the probability distribution function of the errors that can result. From this function, the error can readily be expressed as a standard deviation of error or as the confidence level that the error will be less than a given value View full abstract»

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  • Real-time systems-animation prototyping of formal specifications

    Publication Year: 1991 , Page(s): 51 - 56
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (332 KB)  

    A crucial aspect of the specification process is matching what the specification says the system should do with what the client requires of the system. Many of the above approaches to software development, both formal and informal, have little regard for eliciting the clients opinions on the suitability of a specification. All require, to a greater or lesser degree, a knowledge of abstract notations. How can clients assess a specification written in notations with which they have no experience? Wider acceptance is being sought for formal, mathematical methods for very good reasons, but how much do they contribute to effective communication between specifiers and clients? The authors look at what formal methods are and the benefits that they give and the difficulties that they raise View full abstract»

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  • Transputer implementation of fault tolerant distributed architecture for critical real-time application

    Publication Year: 1991 , Page(s): 239 - 243
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    The systems which perform mission-critical functions, as used in close-loop guidance and event sequencing for various real-time applications consider fault-tolerance as one of their desirable architectural attributes. Such systems are required to be extremely reliable and the work described is an optimistic approach to meet this reliability requirement through a communication architecture of distributed transputers. The fault diagnosis procedure is such that the detection of faulty nodes does not require any central observer and the architecture in true sense remains distributed. The reconfiguration of the system by the replacement of faulty nodes are automatically taken up by the spare nodes. The approach is implemented on eight nodes using multiple 32-bit transputers and the complete software is developed in OCCAM View full abstract»

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  • The effective on-line use of personal computers in conjunction with DCS for enhanced product quality and energy efficiency

    Publication Year: 1991 , Page(s): 284 - 287
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    Energy represents fifteen per cent of the production costs associated with paper manufacture. In 1989 UK Paper's New Thames Mill, the UK's largest producer of high quality printing/photocopying paper, undertook a number of energy related studies using Brighton Polytechnic's Control and Dynamics Research Department for technical support. The authors detail work carried out to ascertain the extent to which a number of quality and process parameters affect steam consumption in the dryer section of the paper machine (J. Grant et al., 1978). A number of energy reduction strategies are then proposed and discussed View full abstract»

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  • Advanced configuration utilities for a real time distributed process control and manufacturing automation platform

    Publication Year: 1991 , Page(s): 194 - 198
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    A large scale collaborative project is underway to implement a distributed platform to support the development of real time applications. Taking advantage of hardware developments such as improved graphics displays, current trends towards distributed processing and the emergence of standards such as OSF/Motif, the platform allows the development and simple integration of sophisticated standards based applications. The development of computerised control and monitoring system (CCMS) applications, based on the platform, for the process and manufacturing industries, is envisaged as a key area for the project. The commercial success of the platform will be aided by making the design and configuration of these applications as reliable and efficient as possible. Unfortunately traditional CCMS implementation methods are slow and error prone. A major part of the project is the development of advanced utilities to overcome these problems. The authors analyse the traditional approach and its inherent difficulties, the advanced utilities to solve these problems and the technologies necessary to support them. Further advanced utilities being considered, and a prototype which is currently under development are also presented View full abstract»

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  • A formalisation of Jackson system development

    Publication Year: 1991 , Page(s): 31 - 39
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    This paper presents a formalisation of the Jackson system development (JSD) method based on the theory of communicating sequential processes (CSP). The paper describes how a specification written in the JSD notations can be translated into CSP, which is well suited for modelling and reasoning about the behaviour of concurrent systems. The translation process is formally defined and a tool has been developed to automate the process. The theoretical basis is extended to cover the JSD implementation phase which has not been previously tackled by other researchers View full abstract»

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  • Methodology and tools for requirements capture, traceability, and verification

    Publication Year: 1991 , Page(s): 46 - 50
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    This paper describes a methodology for establishing a clear requirements baseline at the outset of the development lifecycle using the general approach of procedure SQA01. It was originally applied to software development for a military HF communication system, and has since been applied to two further projects in the civil sector concerning private mobile radio and message switching. The methodology provides forward and reverse traceability between this baseline and the design, so giving assurance that the delivered product meets its requirements whilst not being over-engineered. The methodology helps engineers perform formal integration and acceptance testing such as described in procedures SQA08 and SQA09 by documenting tests and providing traceability to the requirements baseline View full abstract»

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  • The DART real time control system

    Publication Year: 1991 , Page(s): 86 - 92
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (404 KB)  

    This paper describes the radar management and real time control systems designed and developed for the demonstration of advanced radar techniques (DART) radar. The radar management computer controls the distributed radar sub-systems by a sophisticated Ethernet control network aided by real time control signals. This paper outlines the radar management, Ethernet and control hardware and describes the real-time and Ethernet control software View full abstract»

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  • The `PC' as a development environment for real time embedded systems

    Publication Year: 1991 , Page(s): 135 - 138
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    Microprocessor applications consultants can be faced with the design and development of embedded systems for a diverse range of applications and client requirements. Embedded systems by their nature are hardware specific and indicate a need for dedicated development tools; however a more generalised approach often leads to an overall technically superior and more cost effective solution. The author examines the role of a PC in the design and development of an embedded industrial controller for the high speed application of glue. The PC provided support for: software development, software simulation, mechanical design, circuit design, PCB design, driving test equipment, logging data, and displaying test results View full abstract»

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  • Parameter estimation for a non-direct drive robot arm

    Publication Year: 1991 , Page(s): 98 - 103
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    One of the ways of achieving precision control at high speeds for mechanical manipulators is the identification of the parameters of the system and the use of these parameters in a controller such as model based. Viscous friction is one of the parameters whose relatively accurate estimation will lead to significant improvements in a control system. Many authors are currently researching control systems for robots. These control systems are examples of real time software systems. The work reported in the paper concerns the estimation of Coulomb and viscous friction in data from a simulation and from experiments. The requirement for low-pass digital filtering of experimental data is discussed View full abstract»

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  • Choice of design methodologies for demanding high intensity industrial control systems

    Publication Year: 1991 , Page(s): 16 - 21
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (468 KB)  

    There is now a marked increase in the use of computers and programmable electronic systems (PES) for industrial control systems. The principal reason for this is the increased functionality possible that enables systems to either do something that would otherwise be impractical with traditional techniques, or to increase efficiency. In such situations the overall safety of the operator, or the final product often depends on the correct functioning of the computer or PES, and therefore comes under the category of safety-critical computing. The authors discuss the nature of the problem and the choice of design methodologies View full abstract»

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  • Computers operating systems: V-SSTF dynamic disk scheduling technique

    Publication Year: 1991 , Page(s): 254 - 259
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    V-SSTF is a new algorithm which may be turned to FCFS or SSTF by an adjustable parameter that permits the algorithm to be dynamically adapted to changing system conditions. V-SSTF and common strategies including FCFS, SSTF, SCAN, and N-step SCAN are simulated for evaluation purposes. This simulation is programmed using C language and has been implemented on NCR tower machine under Unix. It is used for disk scheduling View full abstract»

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