An implementation of the object-oriented concurrent programming language SINA

SINA is an object-oriented language for distributed and concurrent programming. The primary focus of this paper is on the object-oriented concurrent programming mechanisms of SINA and their implementation. This paper presents the SINA constructs for concurrent programming and inter-object communication, some illustrative examples and a message-based implementation model for SINA that we have used in our current implementation.     

Issues in the design of a parallel object-oriented language

This paper discusses the considerations that have played a role in the design of the language POOL2. This language integrates the structuring techniques of object-oriented programming with mechanisms for expressing parallelism. We introduce the basic principles of object-oriented programming and its significance for program development methodologies. Several approaches for integrating objects and parallelism are compared and arguments for the choices made in POOL2 are presented. We also explain why inheritance is not yet included in POOL2. A brief overview of the research in formal aspects of POOL is given. Finally we indicate some directions for future developments.     

A layered semantics for a parallel object-oriented language

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 programming: the object. This is achieved by structuring the semantics in layers working at three different levels: for statements, objects and programs. For each of these levels we define a specialized mathematical domain of processes, which we use to assign a meaning to each language construct. This is done in the mathematical framework of complete metric spaces. We also define operators that translate between these domains. At the program level we give a precise definition of the observable input/output behaviour of a particular program, which could be used at a later stage to decide the issue of full abstractness. We illustrate our semantic techniques by first applying them to a toy language similar to CSP.This paper describes work done in ESPRIT Basic Research Action 3020,Integration.     

面向对象的方法在移动电话通信仿真测试环境中的应用

该文探讨了面向对象技术在移动通信仿真测试系统中的应用,并介绍了ＳＳＴＥ系统仿真层的设计思想和设计方法。     

An experiment in language design for distributed systems

This paper describes a recent experiment in the design, implementation and application of a programming language designed specifically for distributed systems. The fundamental nature of such systems is used in the derivation of an experimental language, which is described and illustrated. Having outlined an implementation, the project is evaluated and some of the more significant findings are reported. In particular, the paper discusses (and argues for) an explicit language facility for expressing the distribution of a program over an actual system.     

Automated user interface engineering with a pattern reflecting programming language

The development of the user interface concerns all aspects of a software system that are targeted to the interactive delivery of its functionality and data. Today, user interface development accounts for a large proportion of the overall software implementation, while the programming process involves various recurring software patterns. Based on the identification of key commonly occurring user interface programming patterns, we have designed and implemented a user interface programming language with built-in constructs to directly support those software patterns, offering declarative programming features such as: precondition-based actions, unidirectional constraints and data-content monitors. Initially, we introduce the deployment syntax and semantics of the novel programming elements, relying upon subject interaction scenarios. Then we reveal the most demanding implementation aspects of the code generator and the respective run-time library.     

An architectural application framework for evolving distributed systems

In this paper, we present an object-oriented application framework to support the development of evolving distributed systems. The framework combines concepts of the object-oriented paradigm with those of architectural design. The result is a framework which supports extensible and reusable configurations of distributed components. The framework addresses the problem of evolution by allowing the addition, replacement and extension of components of a configuration. Evolution is also possible at run time, where a configuration can change dynamically depending on a particular event. The paper outlines the fundamental aspects of our framework and presents a case study, which illustrates its application.     

Experiences in database system implementation using a persistent programming language

The EXODUS database toolkit, and in particular the E persistent programming language, have been used in two substantial database system implementation efforts by the authors, the Ariel database rule system and the Triton nested relation DBMS. An important advantage of using a persistent programming language for database system implementation is that it is easy to implement special-purpose persistent objects used by the DBMS such as catalogs, rule indexes, and nested relational structures. Support for transactions built into a persistent programming language greatly reduces the effort required to implement a database system. A disadvantage observed is that it is not possible to map the type system of the DBMS to the type system of the underlying programming language while still retaining good performance for ad hoc queries. Also, software engineering difficulties arise when a persistent language makes a distinction between database types and main-memory types.     

An object-oriented architecture for a computer animation system

This paper describes the architecture, capabilities and implementation of The Clockworks, an object-oriented computer animation system encompassing a wide variety of modeling, image synthesis, animation, programming and simulation capabilities in a single integrated environment. The object-oriented features of The Clockworks are implemented in portable C under UNIX using a programming discipline. These features include objects with methods and instance variables, class hierarchies, inheritance, instantiation and message passing.     

Adding graphics to a high-level programming language

When graphics input/output capabilities are added to a programming language originally designed with a text stream input/output model, various design decisions affect the ease with which the graphics facilities are learned and used by applications programmers. In adding window system facilities to the Icon programming language, some design decisions were made very differently from the conventional wisdom, resulting in substantial benefits for programmers. In addition, some pre-existing Icon language features have proved to be useful in graphics programming.     

An Implementation of Constructive Synchronous Programs in POLIS

Design tools for embedded reactive systems commonly use a model of computation that employs both synchronous and asynchronous communication styles. We form a junction between these two with an implementation of synchronous languages and circuits (Esterel) on asynchronous networks (POLIS). We implement fact propagation, the key concept of synchronous constructive semantics, on an asynchronous non-deterministic network: POLIS nodes (CFSMs) save state locally to deduce facts, and the network globally propagates facts between them. The result is a correct implementation of the synchronous input/output behavior of the program. Our model is compositional, and thus permits implementations at various levels of granularity from one CFSM per circuit gate to one CFSM per circuit. This allows one to explore various tradeoffs between synchronous and asynchronous implementations.     

面向对象方法中对象间关系的研究

本文论述了面向对象技术中对象间关系作为第一级建模概念的重要性 ,分析研究了对象间关系在现有面向对象分析、设计以及面向对象程序设计语言中的描述和表达 .针对对象间关系的分析建模和语言实现作了分析 ,指出了现有典型方法的优缺点 ,并总结提出了对象间关系描述和实现的要素     

A semantics of introspection in a reflective prototype-based language

In Malenfant et al. [19], we have described a reflective model for a prototype-based language based on thelookup o apply reflective introspection protocol. In this paper, we augment our previous protocol by converting it to handle continuations reified as first-class objects. First-class continuations provide much more control over the current computation; during the introspection phase fired by message sending, they make it possible not only to change the behavior of the program for that message but also for the entire future computation. In this paper, we provide this introspection protocol with a formal semantics. This result is obtained by exhibiting a mapping from program configurations to priority rewrite systems (PRS) as well as a mapping from message expressions to ground first-order terms used to query the PRS. Other advantages of this approach are: to ensure the termination of the introspection using the smallest set of formally justified conditions and to provide a clear declarative account of this reflective protocol. The PRS also appears as a meta-level to the base language, independent of the implementation, but from which we derive fundamental clues to obtain an efficient language processor. By our new model, we finally highlight the link between reflection in object-oriented languages and the one originally proposed by 3-Lisp [24], although object-orientation provides reusability to reflection, making it easier to use.     

Consensus with a reference state for fractional-order multi-agent systems

This paper investigates consensus of fractional-order multi-agent systems (MASs) with a reference state. First, a consensus control law with a constant reference state is given using graph theory and stability analysis of fractional-order. Then, a general control law and a particular one for consensus of fractional-order MASs with a time-varying reference state are proposed. Next, the above control laws are extended to solve formation tracking problem. Finally, several simulations are presented to verify the effectiveness of the obtained results.     

An object-oriented architecture for knowledge-based production scheduling systems

This paper describes an object-oriented architecture to support decision making in production scheduling environments. An object-oriented world view is used to integrate concepts from discrete event simulation, conventional scheduling logic and artificial intelligence to produce capacity-feasible schedules. The architecture was implemented as a collection of loosely coupled reusable software objects by extending the functionality of software objects from BLOCS/M (Berkeley Library of Objects for Control and Simulation of Manufacturing). Our experience with an industrial prototype is presented.     

Software tools for formation of state spaces of queuing systems with a common type buffer

Universal algorithms and software tools are developed for formation of discrete components of state spaces for queuing systems with a common type buffer. A statement on the parameters of such a buffer is proved. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 3, pp. 164–168, May–June 2007.     

Robust state estimation for a class of uncertain time-delay systems

This paper considers a robust state estimation problem for a class of uncertain time-delay systems. In this problem, the noise and uncertainty are modelled deterministically via an integral quadratic constraint. The robust state estimation problem involves constructing the set of all possible states at the current time consistent with given output measurements and the integral quadratic constraint. This set is found to be an ellipsoid which is constructed via a linear state estimator.     

The evolution of the SR language

As a result of our experience, the SR distributed programming language has evolved. One change is that resources and processes are now dynamic rather than static. Another change is that operations and processes are now integrated in a novel way: all the mechanisms for process interaction — remote and local procedure call, rendezvous, dynamic process creation, and asynchronous message passing — are expressed in similar ways. This paper explains the rationale for these and other changes. We examine the fundamental issues faced by the designers of any distributed programming language and consider the ways in which these issues could be addressed. Special attention is given to the design objectives of expressiveness, simplicity, and efficiency. Gregory R. Andrews was born in Olympia, WA, in 1947. He received the B.S. degree in mathematics from Stanford University in 1969 and the Ph.D. degree in computer science from the University of Washington in 1974. From 1974–1979 he was an Assistant Professor of Computer Science at Cornell University. Since 1979 he has been an Associate Professor of Computer Science at the University of Arizona. During 1983–1984, he was a Visiting Associate Professor of Computer Science at the University of Washington. He has also consulted for the U.S. Army Electronics Command and Cray Laboratories. His research interests include concurrent programming languages and distributed operating systems; he is currently co-authoring (with Fred Schneider) a textbook on concurrent programming. Dr. Andrews is a member of the Association for Computing Machinery (ACM). From 1980–1983 he was Secretary-Treasurer of the ACM Special Interest Group on Operating Systems. He has also been on the Board of Editors of Information Processing Letters since 1979. Ronald A. Olsson was born in Huntington, NY, in 1955. He received B.A. degrees in mathematics and computer science and the M.A. degree in mathematics from the State University of New York, College at Potsdam, in 1977. In 1979, he received the M.S. degree in computer science from Cornell University. He was a Lecturer of Computer Science at the State University of New York, College at Brockport, from 1979 to 1981. Since 1981 he has been a graduate student in computer science at the University of Arizona and will complete his Ph.D. in June 1986. His research interests include programming languages, operating systems, distributed systems, and systems software. Mr. Olsson is a student member of the Association for Computing Machinery.This work is supported by NSF under Grant DCR-8402090, and by the Air Force Office of Scientific Research under Grant AFOSR-84-0072. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes not-withstanding any copyright notices thereon     

Adding classes to the C language: An exercise in language evolution

The C language is a fine tool for writing compact and efficient programs. It is relatively easy to produce good compilers for, and the number of tools available for supporting program- ming in C is large, especially in its ‘home environment’, the UNM system. However, C'S facilities for structuring programs were, until recently, rather limited. To remedy this situation, a data abstraction facility, called classes, was added. The class concept described here has benefitted from the experience gained through a year's use. It is now in use at close to a hundred installations. The guiding principles of the design of C classes were simplicity both in concept and in implementation. Smooth blending of the new facilities into the existing C programming environment was considered essential. Classes can be used without sacrificing the run-time efficiency expected from C. This paper presents some of the reasons why C classes are what they are.