When designing real-time systems, suitable languages are needed due to the special demands of these types of systems. A real-time language must both support modelling of temporal as well as behavioural aspects of the ...
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When designing real-time systems, suitable languages are needed due to the special demands of these types of systems. A real-time language must both support modelling of temporal as well as behavioural aspects of the application. In order to meet the requirements of the more and more complex real-time applications. In this article we will describe an environment which supports both real-time and behavioural modelling, the object-oriented language RealTimeTalk (RTT). The language is based on the well-known Smalltalk paradigm. The choice of Smalltalk as a basis for RTT could be somewhat controversial, but as will be described in the article this is due to the simple syntax of Smalltalk which makes it easier to add and restrict features in the language, and the notion of building applications by components. The environment support design through frameworks. A framework is a well designed and thoroughly tested base for a certain application domain. A framework should also imply a specific design policy for its application domain. The overall goals of the RTT project are thus to simplify the modelling of real-time systems and in these types of systems include predictability and determinism.
Gismo is a highly interactive program, with an iconic human interface and a 3D graphics display, which was developed in order to investigate the feasibility of using object-oriented programming within high-energy phys...
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Gismo is a highly interactive program, with an iconic human interface and a 3D graphics display, which was developed in order to investigate the feasibility of using object-oriented programming within high-energy physics. It allows the user to design a detector and save it to disk, to track Monte Carlo events through such a detector, to simulate the detector response, and to reconstruct an event from this response. Gismo was developed using objective-C and the Interface Builder on a NeXT computer, and the speed with which it was possible to build an application of this complexity indicates that the techniques used warrant further investigation.
An approach to reduce the effect of problems related to inter-node communication in Distributed Problem Solvers (DPS) is presented for the special case of real-time control of Computer Integrated Manufacturing Systems...
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An approach to reduce the effect of problems related to inter-node communication in Distributed Problem Solvers (DPS) is presented for the special case of real-time control of Computer Integrated Manufacturing Systems (CIMS). Some techniques based on the distribution of control and VLSI implementations of control Petri nets were presented in (DEVAPRIYA, 91c; 92a). The present paper discusses the necessity for furnishing the system with a panoplie of diverse communication techniques and letting the system learn to use the best technique for a given situation. This permits a high degree of flexibility of the system without sacrificing unduely on communication efficiency while avoiding bottleneck situations in the DPS network.
Large scale systems have a large number of eigenvalues. Amongst these eigenvalues, only a few of them have noticeable effects on system dynamical behavior. In this paper, a method to identify the importance of each ei...
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Large scale systems have a large number of eigenvalues. Amongst these eigenvalues, only a few of them have noticeable effects on system dynamical behavior. In this paper, a method to identify the importance of each eigenvalue is proposed. Hence an eigenvalue ranking index is used and an expression for its computation is derived. Finally two algorithms to estimate the changes in the ranking indices while system is perturbed are also derived.
object-oriented programming apparently provides a great power to organise and manage all elements constituting a software project in a clean and efficient way. This is particularly not true, however, in a multiple pro...
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object-oriented programming apparently provides a great power to organise and manage all elements constituting a software project in a clean and efficient way. This is particularly not true, however, in a multiple project group-development circumstance. This paper presents an approach to solve these problems in a Smalltalk-type environment. Key ideas are configuration inheritance, version synthesis, and functionality mapping.
Distributed programming can be greatly simplified by language support for distributed communication, such as that provided by remote procedure call (RPC) or remote object invocation. This paper examines design and imp...
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Distributed programming can be greatly simplified by language support for distributed communication, such as that provided by remote procedure call (RPC) or remote object invocation. This paper examines design and implementation issues in these systems, and focuses on the influence of the communication system on a distributed program. To make the discussion concrete, we introduce a single application as implemented in two environments: Modula-2+, an extension of Modula-2 with RPC, and Emerald, an object-based language that supports remote object invocation. We show that small differences in the implementation of the communication system can have a significant impact on how distributed applications are structured.
Emerald is a general-purpose language with aspects of traditional object-oriented languages, such as Smalltalk, and abstract data type languages, such as Modula-2 and Ada. It is strongly typed with a nontraditional ob...
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Emerald is a general-purpose language with aspects of traditional object-oriented languages, such as Smalltalk, and abstract data type languages, such as Modula-2 and Ada. It is strongly typed with a nontraditional object model and type system that emphasize abstract types, allow separation of typing and implementation, and provide the flexibility of polymorphism and subtyping with compile-time checking. This paper describes the Emerald language and its programming methodology. We give examples that demonstrate Emerald's features, and compare and contrast the Emerald approach to programming with the approaches used in other similar languages.
Formalising and automating the software life-cycle processes are key factors in the improvement of software productivity. This paper describes the Project Master Database (PMDB) work, three generations of investigatio...
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Formalising and automating the software life-cycle processes are key factors in the improvement of software productivity. This paper describes the Project Master Database (PMDB) work, three generations of investigations into the modelling and encoding of software life-cycle processes;it briefly describes past activities and concentrates on more recent investigations. It presents an approach to software process modelling based on an object-based model called the PMDB + model, which includes project elements, relationships between those elements and behavioural descriptions of project life-cycle activities. An overview of the model is presented, together with examples to illustrate the application of the model to existing software processes. It also describes a prototyping exercise that implemented the PMDB + model in an object-oriented database management system. Key results of these investigations, the impact of process implementations on the architecture of environments, and lessons learnt from the exercises are described.
The full power of process programming can only be achieved by a system in which we can dynamically design and execute the software process model, as well as the environment which executes the software process model. W...
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The full power of process programming can only be achieved by a system in which we can dynamically design and execute the software process model, as well as the environment which executes the software process model. We are developing a new process modelling strategy (meta-model) called the object process model and an object process modelling environment (meta-environment) OPM, which allows us to design and build both software process models and software development environments that execute the software process models. In the object process model, software process models are not static entities executed by the environment. An executing software process provides a working environment in which software designers can work in order to accomplish a wide variety of software development tasks. In OPM, software process models are described in an object-oriented process programming language called Galois and are executed by the Galois runtime system. OPM itself is written in Galois, and therefore it is considered as a software process running on top of the Galois runtime system. Galois is syntactically a superset of C + + but has four major innovations beyond conventional programming languages: meta-classes, derivation, typed functions and rule-based features. This paper presents the object process model and shows how software process models and software development environments can be designed in the process programming language Galois.
In this article, the development of an action-based process model is described which was especially tailored to the needs of modelling and simulating multifinger hands. The research has been concerned with a descripti...
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In this article, the development of an action-based process model is described which was especially tailored to the needs of modelling and simulating multifinger hands. The research has been concerned with a description technique using constraints for modelling the working environment and with the design of an appropriate process model for simulating complex movements of manipulation objects with multifinger hands. The paper presents the results of an object-oriented approach to the proposed model and consists of two parts: a constraint net that describes the connections and relations between cell components (robots, grippers, objects) in the working environment and a propagation algorithm that computes the new locations regarding the modifications and logical dependencies.
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