Showing papers on "Object-oriented design published in 1983"

Spatial Planning: A Configuration Space Approach

Abstract: This paper presents algorithms for computing constraints on the position of an object due to the presence of ther objects. This problem arises in applications that require choosing how to arrange or how to move objects without collisions. The approach presented here is based on characterizing the position and orientation of an object as a single point in a configuration space, in which each coordinate represents a degree of freedom in the position or orientation of the object. The configurations forbidden to this object, due to the presence of other objects, can then be characterized as regions in the configuration space, called configuration space obstacles. The paper presents algorithms for computing these configuration space obstacles when the objects are polygons or polyhedra.

Software version management system

Abstract: A software version management system, also called system modeller, provides for automatically collecting and recompiling updated versions of component software objects comprising a software program for operation on a plurality of personal computers coupled together in a distributed software environment via a local area network. The component software objects include the source and binary files for the software program, which stored in various different local and remote storage means through the environment. The component software objects are periodically updated, via a system editor, by various users at their personal computers and then stored in designated storage means. The management system includes models which are also objects. Each of the models is representative of the source versions of a particular component software object and contain object pointers including a unique name of the object, a unique identifier descriptive of the cronological updating of its current version, information as to an object's dependencies on other objects and a pathname representative of the residence storage means of the object. Means are provided in the system editor to notify the management system when any one of the objects is being edited by a user and the management system is responsive to such notification to track the edited objects and alter their respective models to the current version thereof.

Distributed Software System Design Representation Using Modified Petri Nets

Abstract: A model for representing and analyzing the design of a distributed software system is presented. The model is based on a modified form of Petri net, and enables one to represent both the structure and the behavior of a distributed software system at a desired level of design. Behavioral properties of the design representation can be verified by translating the modified Petri net into an equivalent ordinary Petri net and then analyzing that resulting Petri net. The model emphasizes the unified representation of control and data flows, partially ordered software components, hierarchical component structure, abstract data types, data objects, local control, and distributed system state. At any design level, the distributed software system is viewed as a collection of software components. Software components are externally described in terms of their input and output control states, abstract data types, data objects, and a set of control and data transfer specifications. They are interconnected through the shared control states and through the shared data objects. A system component can be viewed internally as a collection of subcomponents, local control states, local abstract data types, and local data objects.

Object building method for self configuring computer network

Abstract: A computer system including a first processor and a plurality of removable interface circuits is operated by storing hardware descriptors for each interface circuit, each hardware descriptor including a name and an attribute of each component of the interface. Software templates describing each data structure and pointers to code to be executed to build software objects corresponding to each component contained on any interface board in the system are stored, which code is executed to building such software objects. The hardware descriptors are utilized to obtain lists of components of each interface from a data base, using names of such components to obtain software templates corresponding to the named component and pointing to software that utilizes the software template to build the software object representing a function that can be performed by the component, assigns a name to that software object and entering the name and corresponding software object into the data base.

Towards the Design and Implementation of Object Oriented Architecture

Abstract: Object oriented programming languages and the computer architecture to support the reliable and efficient execution of programs written in these languages are important issues for providing better programming environment. The main purpose of this paper is to establish the foundation for the design and implementation of object oriented programming languages and object oriented architecture. First, various definitions for object in existing languages and systems are surveyed. Then a new model of object and computation on objects is introduced to establish the foundation. A new object oriented language is used both to rationalize the model and to exemplify how the model is applied to object oriented languages. Finally, issues in the design and implementation of an object oriented architecture which directly reflects this model is described.

Transformations of software design and code may lead to reduced errors

Abstract: The capability of programmers and non-programmers to specify problem solutions by developing example-solutions and also for the programmers by writing computer programs was investigated; each method of specification was accomplished at various levels of problem complexity. The level of difficulty of each problem was reflected by the number of steps needed by the user to develop a solution. Machine processing of the user inputs permitted inferences to be developed about the algorithms required to solve a particular problem. The interactive feedback of processing results led users to a more precise definition of the desired solution. Two participant groups (programmers and bookkeepers/accountants) working with three levels of problem complexity and three levels of processor complexity were used. The experimental task employed required specification of a logic for solution of a Navy task force problem.