Showing papers on "Implementation published in 1982"

Experience with Formal Specifications Using an Extended State Transition Model

Abstract: Experience with the use of formal descriptions of communication services and protocols is described. The paper focuses on the experience of the authors with the extended state transition model which is proposed as a standard formal description technique (FDT) for the services and protocols in the OSI environment. The first part of the paper refers to various example specifications, including transport protocol and service specifications, and discusses the suitability of the specification method and possible extensions. In the remaining part, the use of such formal specifications during the phases of system design, implementation, and testing is described. Various approaches to protocol design validation, implementation, and assessment of implementations are discussed, with emphasis on the last point. The experience with several of these approaches is described in the paper, and further details may be found in the references.

Uniformity in user-computer interaction languages: a compromise solution

Abstract: To alleviate the user problems associated with the diverse implementations of user-computer interaction languages, the use of an intermediary processor to “uniformize” the languages is presented. Such processing is characterized in terms of required intermediary actions and logical capabilities. The supportive NBS facilities are portrayed and an example application, using a common command language to access five bibliographic retrieval systems, is described.

Analysis and Specification of Office Procedures

Abstract: Conventional approaches to "office automation" focus on the lowest common denominator of office work: typing, filing, filling in forms, etc. As a consequence, the process of office systems analysis lacks tools and techniques that address the office in terms of business functions rather than as manipulation of paper artifacts. The Office Specification Language (OSL) and its associated analysis methodology have been developed as a means of implementing a functional approach to office procedure analysis and description. OSL is based on several premises derived from a study of office systems analysis at a functional level: -There exist high-level constructs common to a wide variety of disparate offices. A structured formal language built upon such standardized abstractions can be useful in helping an analyst approach, understand, and describe the operations of many offices. -Office procedures deal with (abstract) objects, not paper forms. Forms and other documents are not basic to office operations: they are mechanisms for organizing and transmitting information about some more fundamental object. Therefore office analysis should focus not on forms, but rather on the underlying business requirements that must survive any change in system implementation. -Office procedures are fundamentally simple; their apparent complexity is not inherent, but due to a myriad of special cases, historical accretions, and implementation details. Identification of a procedure''s core requirements is the framework upon which analysis should be based. Such an understanding is a prerequisite to effective reorganization of and design of support systems for office functions. OSL is postulated to be of utility for office analysis and systems design. Field tests of the language and methodology have shown that our basic approach is effective for analysis purposes, and have identified directions for further improvements.

The Performance Evaluation of Control Implementations

Abstract: A methodology for the experimental investigation of the implementation of control in programming languages is presented. The methodology specifies a data-collection technique, the environment for driving simulations of control implementations, and a meaningful metric for performance evaluation. The key in the methodology is the separation of activity which is affected by the control implementation from that which is not.

Transformation of ADA Programs into Silicon

Abstract: : This report outlines the beginning steps taken in an integrated research effort toward the development of a methodology, and supporting systems, for transforming Ada programs, or program units, (directly) into corresponding VLSI systems. The time seems right to expect good results. The need is evident; special purpose systems should be realistic alternatives where simplicity, speed, reliability, and security ae dominant factors. Success in this research can lead to attractive options for embedded system applications. Ada programs can be regarded as ensembles of machines, one per program unit (module), which in turn may be mapped directly into corresponding VLSI structures on one or more chips with interconnecting (packet switched or other) communication nets. The research reported here is part of a five-year plan, the first year of which focuses on 'proving' the concepts through a realistic demonstration of methodology for a specific example Ada program (a silicon representation of part or all of the DoD Standard Internet Protocol, IP, initially expressed in Ada). Implicit in these objectives is the development of a set of hardware structuring paradigms (rewrite rules) whose application can ensure that transformation steps between levels of abstraction in the design process are well structured in order to preserve the integrity and, where possible, the clarity of the original Ada specification. Some paradigms, but of course not all, lead to highly efficient implementations.

The Evaluation of Optimization Software for Engineering Design

Abstract: The design and implementation of two major comparative experiments is reviewed with particular emphasis on testing methodology. These studies took place at Purdue University. The first, an investigation of the merits of general purpose nonlinear programming codes with major funding from the National Science Foundation, was conducted over the period 1973 to 1977. The second, an investigation of the relative merits of various geometric programming strategies and their code implementations with funding from the Office of Naval Research, was conducted over the period 1974 to 1978. The various major decisions associated with such studies are discussed, such as the selection and collection of problems and codes, the nature of data to be collected, evaluation criteria, ranking schemes, presentation and distribution of results, and the technical design of the experiment itself. The statistical implications of the results in light of the experiment design are examined, as are the effects of various experiment parameters Such as number of variables, number of constraints, degree of nonlinearity in the objective and constraints, and starting point placement. Finally, recommendations for future experiments are given.

Effect of declarations on software metrics: An experiment in software science

Abstract: The attractiveness of software science [HAL77] is to some extent due to the simplicity of its instrumentation. Upon learning the detailed rules of counting operators and operands, the experiments and derivations using various algorithms and languages can be repeated. Proposed or actual applications of software science are quite varied (For example, see [SEN79]). The size and construction time of a program can be estimated from the problem specification and the choice of programming language. An estimate of the number of program bugs can be shown to depend on programming effort. Optimal choice of module sizes for multimodule implementations can be computed. Elements of software science have applications to the analysis of technical prose.The purpose of this experiment is three fold. First, we want to apply software science metrics to the language 'C'.The second purpose of the experiment is to study the effect of including declaration statements while counting operators and operands.Finally, we have set out to determine whether the area of application has any influence on software science metrics.

Implementation of automated medical information systems in the air force medical service

Abstract: The use of optimal automated system implementation strategies is essential where the resources for system support are scarce. The strategies used in a successful implementation are examined. A counterpoint of a similar system that failed is discussed, but the focus of success refinement is used to find the optimal strategy.

About the Portability of the DIDASS-Package (an IBM Implementation)

Abstract: The aim of this paper is to point out the portability of the program package for linear multiple criteria reference point optimization. This should be understood as a step to improve the user-oriented feature of software developed at IIASA and can be an example for further implementations of the software on other computer systems. The actual reason for transferring the DIDASS-package to INSEE is the need for solving problems of medium- and long-term planning for the national economy of France which can be described by dynamic multiple-criteria linear programming models. This paper is an initial note on implementation problems. As soon as there is substantive application in INSEE it will be reported. We first describe the implementation problems, then the solutions and an hypothetical example to demonstrate the workability of the software.

Department of Defense Weapon System Acquisition Policy: A System Dynamics Model and Analysis.

Abstract: : A dynamic policy model of the DoD acquisition system has been developed and tested. The model provides a broad-based structure of the weapon acquisition system that can be used as a base for the testing and evaluation of alternative acquisition policies. Sources of information used in model development include both literature research and personal interviews with DoD, Air Force, Congressional, and OMB personnel active in the operation and analysis of the acquisition system. The model structure is built around a system goal of providing approximate parity in total capability, in the aggregate, of operational US and Soviet weapon systems. Emphasis is placed on the dynamic relationships within the acquisition system and how they are impacted by DoD policy and external pressures. Use of the model for policy analysis provides information on trends within the acquisition system as policy implementations or changes are tested.

User-Oriented Performance Measurements of the ARPANET: The Testing of a Proposed Federal Standard

Abstract: This report presents the results of a trial implementation of a newly developed data communication performance measurement methodology which has been proposed as Federal Standard 1043. In this experiment, a prototype data communication performance measurement system was developed in accordance with specifications defined in the standard. The system was used to assess the data communication service provided to a typical pair of ARPANET end users (host computer application programs). These user-oriented measurements differed from earlier ARPANET measurements in that the host computer operating systems and network control programs were regarded as providers of an end-to-end data communication service, rather than as users of the subnetwork. Results of the experiment will be useful in three ways. First, the prototype performance measurement system developed in this experiment will facilitate future implementations of the measurement standard. Second, the experience of implementing the measurement standard identified a number of ways in which that standard could be improved. These improvements will be incorporated in a future revision. Finally, the user-oriented performance values measured in this experiment will assist communication system planners in relating end-to-end performance objectives to the performance of subsystems.

Specifying and implementing object managers in Ada

Abstract: An outline of a formalism for writing specifications of synchronisation behaviours is given, together with a sketch of an approach to the transformation between such a specification and an implementation in Ada. The model of implementation is that each specification is regarded as defining a mechanism, the 'object manager', which controls the occurrence of events in the system. Each object manager is implemented as an Ada package that provides a collection of procedures to a collection of tasks. Hidden inside the package are 'shared' data structures and a synchronisation task which schedules the start of execution of each procedure call.