The ways in which a persistent programming language allows the reuse of data and code objects by preserving them as persistent objects is discussed. The programming language chi , which supports persistent programming...
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The ways in which a persistent programming language allows the reuse of data and code objects by preserving them as persistent objects is discussed. The programming language chi , which supports persistent programming, is described. The language is innovative in that it elevates capabilities to the programming level and gives the programmer a convenient way to express which objects are persistent independently of the type of object. Thus, it provides orthogonal persistence. A further advantage that follows from such use of capabilities is that chi provides an implementation path for persistence, even upon architectures that do not support capabilities directly.
The authors have developed an architecture simulation toolkit from which a RISC simulator has been built by employing object-oriented software development techniques. object-oriented design makes it easy to extend the...
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The authors have developed an architecture simulation toolkit from which a RISC simulator has been built by employing object-oriented software development techniques. object-oriented design makes it easy to extend the simulated RISC architecture. Equally, more or even different functionality can be incorporated by uniformly extending the framework of the simulator. The basic framework is explained by simulating a subset of the Acorn ARM RISC's instruction set. This instruction set is then extended to provide further functionality by the addition of a multiply with accumulate instruction. The reader is expected to be reasonably conversant with the C+ + programming language and with the basic concepts of object-oriented programming.
A Distributed Problem Solving (DPS) architecture (SCOPE) for the control of Flexible Manufacturing Systems is presented. The controller kernel is intended to be easily adapted for different manufacturing systems, and ...
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A Distributed Problem Solving (DPS) architecture (SCOPE) for the control of Flexible Manufacturing Systems is presented. The controller kernel is intended to be easily adapted for different manufacturing systems, and we propose this as a basis for the standardization of control architectures from the point of view of control system designers. Our concern is the dynamic (rapid) generation of flexible solutions to a control problem with several discrete decision variables. Each node consists of the object class (or classes) that it deals with, its local model (which describes the dynamics of the node), and a set of problem solving agents (knowledge sources), that could be invoked by this node. An object class is represented by a Petri net with an object orientated interpretation (PNO), and acts as a structured local database or a local hypothesis register. The local model indicates the conditions under which this problem solving node could invoke any of its agents, and also when a node demands the services of another node, this demand is formulated through the local model. A node calling for the treatment of its local hypothesis modification does not know the node which will respond. Inside a node its KSs are also disconnected (uncoupled), and react in an opportunistic manner. This control structure permits parallel activation of KSs. The protocols for activation, running, termination (normal and abnormal) and resumption of the different KS types are specified with generic Petri net structures. A detailed description of the problem solving mechanism in SCOPE is given for the activities involving the Batching node.
Cell control forms an important layer in a hierarchy of control. A cell will typically contain several machine tools, robots and allied material handling equipment. The function of a cell controller is to co-ordinate ...
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Cell control forms an important layer in a hierarchy of control. A cell will typically contain several machine tools, robots and allied material handling equipment. The function of a cell controller is to co-ordinate and control the equipment within the cell so as to achieve high degrees of efficiency. A requirement is that the cell controller should function in real-time. The need to maintain high cell efficiency while having relatively low computation times poses a severe requirement on the design of a cell controller. Previous cell controller predominantly either suffer from relatively long computation times or else handle only a portion of the cell control functions. The aim of this paper is to give a detailed description of the operation of X-Cell, a cell control system that uses object-oriented programming to map cell control functions onto objects. The language used is Scheme, with Scheme objectorientedprogramming System (SCOOPS) providing the object-oriented paradigm. The paper gives a brief overview of the architecture of X-Cell, together with a more detailed description of each of the three main modules: the scheduler, operation dispatcher, and monitor. A brief description of the X-Cell emulator is then given. Finally, an example scenario using X-Cell is given. The overall result is a cell control system that can be adapted for use in a wide variety of manufacturing cells.
Three object-oriented analysis methodologies and three object-oriented design methodologies are reviewed and compared to one another. The authors' intent is to answer the question of whether emerging object-orient...
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Three object-oriented analysis methodologies and three object-oriented design methodologies are reviewed and compared to one another. The authors' intent is to answer the question of whether emerging object-oriented analysis and design methodologies require incremental or radical changes on the part of prospective adopters. The evolution of conventional development methodologies is discussed, and three areas-system partitioning, end-to-end process modeling, and harvesting reuse-that appear to be strong candidates for further development work are presented
In this paper, we present a formal requirement specification language, frame-and-rule oriented requirement specification language FRORL, which was developed to facilitate the specification, analysis, and development o...
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In this paper, we present a formal requirement specification language, frame-and-rule oriented requirement specification language FRORL, which was developed to facilitate the specification, analysis, and development of a software system. The surface syntax of FRORL is based on the concepts of frames and production rules which may bear hierarchical relationships among each other, relying on multiple inheritance. However, to provide thorough semantic foundations, FRORL is based on a nonmonotonic variant of Horn-clause logic. Using the machinery of Horn-clause logic, various properties of a FRORL specification can be analyzed. The underlying logic of FRORL has been proven sound and complete. Among the external properties of FRORL are formality, object-orientedness, and wide-spectrum of life cycle phases;intrinsic properties are modularity, provision for incremental development, inheritance, refinement, re-usability, prototyping, and executability;and there is a surrounding environment including a knowledge base, theorem proving support, and graphic support. A software development environment based on FRORL has been implemented using C on a Sun workstation.
This paper introduces a model that combines and extends capabilities of relational and objectoriented systems. Within a simple, statically-typed framework, the model supports abstract data types (ADTs), a multiple in...
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Technological advancements i n programming methodologies and computational power have made expert systems an economical and important solution for manufacturing process control. Expert systems have been widely accepte...
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We develop a denotational semantics for POOL, a parallel object-oriented programming language. The main contribution of this semantics is an accurate mathematical model of the most important concept in object-oriented...
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