The distributed programming language SR—Mechanisms,design and implementation

SR is a new language for programming software containing many processes that execute in parallel. The language allows an entire software system that controls a potentially large collection of processors to be programmed as an integrated set of software modules. The key language mechanisms are resources, operations and input statements. The language supports separate compilation, type abstraction, and dynamic communication links; it also contains novel treatments of arrays and procedures. This paper gives an overview of the language mechanisms, discusses some of the major design decisions and describes one implementation.     

An object-oriented constraints-based system for concurrent product development

This research work aims to develop an intelligent constraint-based system that enables designers to consider at the early stages of the design process all activities associated with product’s life cycle. One of the most important aspects of these activities is the evaluation and optimisation of manufacturing processes that require various type of information from the different aspects of product’s life cycle. This research article discusses the development of a prototype system for manufacturing process optimisation using a combination of both mathematical methods and constraint-programming techniques. This approach enables designers to evaluate and optimise feasible manufacturing processes in a consistent manner as early as possible during the design process. This helps in avoiding unexpected design iterations that wastage a great amount of time and effort, leading to longer lead-time. The development process has passed through the five major stages: Firstly, an intelligent constraint-based design system for concurrent product and process design has been developed. Secondly, a manufacturing process optimisation module has been constructed. Thirdly, the product features, processes, cost, time and constraints to be used for carrying out various design tasks has been represented in the format of constraints, frames, objects, and rules. Fourthly, the process optimisation and evaluation rules for the selection of feasible processes for complex features, and finally, the information management system that ensures consistency in information exchange and decision making activities have been developed.     

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.     

Visual Zero: A persistent and interactive object-oriented programming environment

In this article, an ongoing research project held in the Computer Science department of the University of Vigo is described. Its main objective is to develop an interactive object-oriented environment, serving as a vehicle for learning object-oriented programming. It currently consists of a virtual machine, an assembler, compilers for two high-level programming languages, and an educational visual programming environment. Its main characteristics are (a) the support of prototype-based object orientation, which is a model of object orientation that actually wraps the class-based model; (b) the support for object persistence, which simplifies all input/output issues to the minimum, and (c) the availability of a new visual programming environment is an invaluable help. We the authors think that the combination of all of these possibilities, will lead to an interesting, useful tool that would be recommended for object-oriented teaching. The whole system has been successfully employed in a number of different courses, allowing students to concentrate on objects and their relationships from the very beginning, and thus helping them to achieve a high degree of knowledge about the object-oriented programming paradigm.     

TGMS: An object-oriented system for programming geometry

TGMS (tiered geometric modelling system) is an experimental system intended to reduce the difficulty and cost of developing new solid modelling applications while preserving investment in an existing, time-tested, solid modeller. The application developer writes programs in the TGMS language, which consists of a base language augmented by data types (classes) for geometry. The base programming language is AML/X, an object-oriented language intended for use in design and manufacturing applications. Solid modelling is done using an interface to GDP (geometric design processor), an existing, production-quality solid modelling system. TGMS shows how a system written in a non-object-oriented language can be used as a base for an object-oriented application programming environment. This paper presents the design of TGMS and discusses important aspects of its implementation. The TGMS language defines classes and methods that provide an interface to functions and data represented in a non-object-oriented language. To implement TGMS, issues related to communication, storage management and consistency were addressed. These, and other, implementation issues are discussed. The paper includes sample programs and a summary of feedback from TGMS users. It concludes that the use of object-oriented programming for geometry has many benefits, and that an object-oriented system can be built on top of a non-object-oriented system at less cost than building the equivalent object-oriented system from scratch.     

Concurrent C: A programming language for distributed multiprocessor systems

Recent advances in hardware technology have made the construction of multiprocessor systems economically feasible. This paper describes a new programming language (Concurrent C) suitable for distributed systems which are networks of loosely connected processors, each with its own local storage. Concurrent C is the extended version of the programming language C, incorporating features for parallel processing and interprocess communications.     

LMNtal as a hierarchical logic programming language

LMNtal (pronounced “elemental”) is a simple language model based on hierarchical graph rewriting that uses logical variables to represent connectivity and membranes to represent hierarchy. LMNtal is an outcome of the attempt to unify constraint-based concurrency and Constraint Handling Rules (CHR), the two notable extensions to concurrent logic programming. LMNtal is intended to be a substrate language of various computational models, especially those addressing concurrency, mobility and multiset rewriting. Although the principal objective of LMNtal was to provide a unifying computational model, it is of interest to equip the formalism with a precise logical interpretation. In this paper, we show that it is possible to give LMNtal a simple logical interpretation based on intuitionistic linear logic and a flattening technique. This enables us to call LMNtal a hierarchical, concurrent linear logic language.     

An object-oriented approach to application generation

The TUBA system consists of a set of integrated tools for the generation of business-oriented applications. Tools and applications have a modular structure, represented by class objects. The article describes the architecture of the environments for file processing, screen handling and report writing.     

An object-oriented real-time programming language

The real-time object model, an extended object-oriented model for describing real-time systems, is described. The design and implementation of RTC++, a programming language that extends C++ on the basis of the real-time object model, are discussed. The schedulability analysis and specification of rigid timing constraints in systems with active objects are reviewed     

Distributed dynamic programming using concurrent object-orientedness with actors visualized by high-level Petri nets

This paper deals with application of concurrent object-oriented programming with Actors to solve dynamic programming problems in a distributed computing environment. This area of research is often called distributed artificial intelligence. Using a dynamic programming example of chained matrix multiplication, a method of managing dynamic programming searches in a distributed programming environment with Actors is presented. Distributed computations with Actors are visualized by means of Time-Varying Automata (for cases with no intra-actor concurrency) or using a class of high-level nets called Hierarchical Colored Petri Nets (for cases with intra-actor concurrency). Design and implementation features of the specific Actor-based programming environment, using a concurrent extension of C++, are also discussed.     

A comparison of object-oriented programming in four modern languages

Object-oriented programming has become a widely used, important programming paradigm that is supported in many different languages. C++ has become the most widely used object-oriented language and many C++ programmers are unfamiliar with the different approaches taken by other languages in the paradigm. This paper is intended as an introduction to a broad range of ideas in object-oriented programming. Specifically, we introduce four modern programming languages that support object-oriented programming (Oberon-2, Modula-3, Sather and Self), and show how a simple application is coded in these languages. While each of these programming languages provide support for inheritance, dynamic dispatch, code reuse, and information hiding, they do so in very different ways and with varying levels of efficiency and simplicity. The use of a simple example, based on a common programming problem, facilitates our comparison. We have coded the application in all of these languages, including C++, and we compare the compile times, object code sizes, and run times of the available implementations. Implementations of all the languages compared and all of the programs we measure are available on the Internet. Ultimately, our goal is to encourage and facilitate programmers in understanding and exploring a variety of object-oriented programming languages.     

Multiple robot programming using a concurrent logic language

Advances in robotics has led to the cooperation of multiple robots among themselves and with their industrial automation environment. Efficient interaction with industrial robots thus becomes one of the key factors in the successful utilization of this modern equipment. When multiple manipulators have to be coordinated, there is a need for a new programming approach that facilitates and encompasses the needs of concurrency, synchronization, timing, and communication. Most robot languages have been developed with little attention being given to the integration of the robot with its environment. Currently, there is a gap between the robot capabilities, the task definition environment, and language facilities supplied to use robots.This paper analyzes the needs and then establishes that a concurrent logic programming approach is a step towards achieving a multi-robot knowledgeable task programming. In particular, the FCP dialect of concurrent Prolog is demonstrated, and analyzed.This research is partially supported by the Paul Ivanier Center for research in robots and production management.     

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.     

Optimal concurrent design based upon distributed product development life-cycle modeling

This research introduces an optimal concurrent design approach based upon a previously developed distributed product development life-cycle modeling method. In this approach, the product realization process alternatives and relevant activities are modeled at different locations that are connected through the Internet. Relations among these alternative activities are described by an AND/OR graph. The optimal product realization process alternative and its parameter values are identified using a multi-level optimization method. Genetic programming (GP) and particle swarm optimization (PSO) are employed for identifying the optimal product realization process alternative and the optimal parameter values of the feasible alternatives, respectively.     

Object oriented implementation of distributed finite element analysis in .NET

The paper describes a detailed study into the object-oriented implementation of distributed finite element analysis on desktop computers using the .NET framework. The software design aspects are described in some detail for both direct and iterative solution algorithms. The use of interfaces played an important role in the software design. This, together with the .NET framework, enabled remote objects to be implemented in a relatively seamless fashion. The solution routines were “blind” to whether the objects were local or remote. Numerical tests were carried out and reasonable speed-up was achieved, particularly for direct solution methods. It is concluded that .NET provides a viable framework for implementing distributed computing on networks of personal computers.     

Petri net-based analysis on object assignment in distributed object-oriented systems

Object-oriented programming ^[9], which treats objects as processes in execution, has shown significant effectiveness in distributed systems. This effectiveness is greatly influenced by how objects are assigned to nodes. In this paper, we present a colored generalized stochastic Petri net (CGSPN) model to analyze the behavior of object invocations when an assignment strategy is applied. The effectiveness of an object assignment is also analyzed by our CGSPN model. Moreover, this analysis provides guidelines to develop an efficient object assignment strategy. ^[4–8]     

Distributed finite element computations using object-oriented techniques

An object-oriented parallel finite element framework has been developed to facilitate rapid prototyping of a wide variety of parallel finite element computations. Parallel computing and object-oriented technologies are integrated to achieve efficiency in both computation and software development. The paper presents various reusable and extensible components that constitute the parallel finite element architecture.