Software for an air pollution measuring system: An application of modula

The program for a small embedded computer system has been implemented in Modula. The execution speed of this program was particularly important and the speed achieved was adequate. Some parts of this program are described using a notation derived from the Mascot approach. The use of the Mascot notation with a module-structured language is discussed and some suggestions for an appropriate style are made. Some simple optimizations of the program were made in order to achieve increased execution speed and it was observed that the final program ran at about twenty times the rate of an equivalent Fortran program. Some points on the suitability of Modula are briefly discussed and, in a similar way to previous authors, it is concluded that Modula is suitable for applications of this type.     

A modula based language supporting hierarchical development and verification

This paper describes a proposal for a modification to the language Modula. The modification was motivated by a desire to bring to the language the ability to build hierarchical systems and to support program verification efforts. In the modified language, called SB-Mod, modules are grouped into levels and calls are permitted from the modules of one level to those of a higher level. Verification is supported through a set of clearly described synchronization constructs and by restricting the flow of information between levels. A result of this is that levels do not interfere with each other and can be treated separately for purposes of verification. In considering modifications, an attempt was made to provide the user with a variety of control mechanisms, while at the same time avoiding situations in which excessive run-time overhead would be incurred.     

The use of modula

Three sample programs are developed and explained with the purpose of demonstrating the use of the programming language Modula. The examples concentrate on the uses of modules, concurrent processes and synchronizing signals. In particular, they all focus on the problems of operating peripheral devices. The concurrency of their driver processes has to occur in real time. The devices include a typewriter, a card reader, a line printer, a disk, a terminal with tape cassettes and a graphical display unit. The three programs are listed in full.     

Design and implementation of modula

This paper gives an account of some design decisions made during the development of the programming language Modula. It explains the essential characteristics of its implementation on the PDP-11 computer, in particular its run-time administration of processes and the mechanism of signalling. The paper ends with some comments on the suitability of the PDP-11 for this high-level multiprogramming language.     

An algorithm for generating abstract syntax trees

In this paper, we discuss the notion of an abstract syntax. An algorithm is presented for automatically deriving an abstract syntax directly from a BNF grammar. The implementation of this algorithm and its application to the grammar for Modula are discussed.     

The suitability for master/slave concurrency of concurrent euclid,ada and modula

The suitability of Concurrent Euclid, Ada and Modula for a special form of asynchronous concurrency, called master/slave concurrency, is investigated. No language is ideal, with Concurrent Euclid and Modula having major drawbacks. The conclusion lists the features desirable in a language for master/slave concurrency.     

Implementation of the database programming language modula/R on the personal computer lilith

Modula/R is a database programming language that integrates the programming language Modula-2 and the relational database model. This paper describes the language concepts of Modula/R and its implementation on the personal computer Lilith within the database project LID AS. A transaction concept as an extension of the procedure concept is integrated into Modula/R to support its implementation in a multi-user environment with access to shared distributed databases through a network of personal computers.     

RTO: An overview and assessment of current practice

The practice of implementing real-time optimization (RTO) using a rigorous steady-state model, in conjunction with model predictive control (MPC), dates back to the late 1980s. Since then, numerous projects have been implemented in refinery and chemical plants, and RTO has received significant attention in the industrial and academic literature. This history affords us the opportunity to assess the impact and success of RTO technology in the process industries. We begin with a discussion of the role RTO serves in the hierarchy of control and optimization decision making in the plant, and outline the key steps of the RTO layer and the coordination with MPC. Where appropriate, we point out the different approaches that have been used in practice and discuss the success factors that directly relate to the success of RTO within an organization. We also discuss alternative approaches that have been used to alleviate some of the challenges associated with implementing RTO and which may be appropriate for those unwilling to commit to the traditional RTO approach. Lastly, we provide suggestions for improvement to motivate further research.     

From modula to oberon

The programming language Oberon is the result of a concentrated effort to increase the power of Modula-2 and simultaneously to reduce its complexity. Several features were eliminated, and a few were added in order to increase the expressive power and flexibility of the language. This paper describes and motivates the changes. The language is defined in a concise report¹.     

The Variety of Variables in Automated Real-Time Refinement

The refinement calculus is a well-established theory for deriving program code from specifications. Recent research has extended the theory to handle timing requirements, as well as functional ones, and we have developed an interactive programming tool based on these extensions. Through a number of case studies completed using the tool, this paper explains how the tool helps the programmer by supporting the many forms of variables needed in the theory. These include simple state variables as in the untimed calculus, trace variables that model the evolution of properties over time, auxiliary variables that exist only to support formal reasoning, subroutine parameters, and variables shared between parallel processes.     

An efficient protocol with synchronization accelerator for multi-processor embedded systems

With the proliferation of multi-processor core systems, parallel programming imposes a difficult challenge where current solutions are far from being considered efficient. In order to alleviate the difficulty of parallel programming, we propose a scheduler, which is part of a master–slave RTOS, to efficiently manage the parallel programs running on a multi-processor core system. We also propose an efficient protocol that serves as the interface between the operating system and application programs. This interface protocol runs on a dedicated control subnet to cut down the synchronization overhead between the parallel tasks. Such synchronization overhead incurred in these multi-core parallel systems has been recognized as one of the severe limiting factors when pushing up the performance envelope. Experimental results, obtained from the register-transfer level simulations of various benchmark parallel programs, show that the proposed protocol and the control subnet can improve the system efficiency by up to 33.5%. This protocol, as it is designed to be compatible with the minimum subset of the massage-passing interface functions (MPI), scales well with the number of cores.     

三分仓回转式空预器通用模块化仿真模型

在培训用仿真模型的基础上,将工程上性能计算方法融入回转式空预器动态仿真模型中,从而提高了模型的精度。在STAR-90仿真支撑软件提供的建模环境下,将所建立的数学模型转化成一个具有标准化结构的通用算法模块。采用模块化建模方法,复用此算法模块,并通过各模块输出、输入变量名的连接的方式,建立了三分仓回转式空气预热器的多段仿真模型,从而校正了单段集中参数模型动态趋势中存在的某些错误响应。所建仿真模型,既可用于电站仿真机的开发,又可用于工程上对空预器的性能设计、分析。     

实时控制系统的面向对象软件结构与实现方法

商品化的复杂实时控制系统不仅要具备实时控制与监测功能，而且能让用户自己开发控制策略，生成监视画面，管理运行数据。这种集实时控制，ＣＡＤ，数据库于一身的软件系统必然较庞大，复杂，而良好的软件结构与实现方法则克服软件系统复杂性的关键，也是整个系统成败的关键，本文提出了这类复杂系统的新的软件结构以及基于面向对象编程（ＯＯＰ）的实现方法。     

An Introduction to Real-Time Object-Z

This paper presents Real-Time Object-Z: an integration of the object-oriented, state-based specification language Object-Z with the timed trace notation of the timed refinement calculus. This integration provides a method of formally specifying and refining systems involving continuous variables and real-time constraints. The basis of the integration is a mapping of the existing Object-Z history semantics to timed traces. Received September 2000 / Accepted in revised form June 2001     

实时虚拟舞台系统灯光效果的实现

在舞台排练系统中,经常有上百盏不同式样的灯同时照亮场景的情况发生,但是目前图形处理器硬件只支持8盏灯同时点亮,而且大多数渲染引擎只提供点光源、聚光源和方向光源三种灯光模型.为了实时模拟真实的效果,使用了一个称为超级椭圆的光源模型,它可以把各种不同形状的灯的式样预先计算出并保存在纹理贴图中,这样后期计算光强度时只要从纹理中获得即可.此外,还提出如何进行光照优化,减少不必要计算,使所有灯都能发挥作用的方法.通过测试,系统达到了令人满意的实时帧数和效果.     

Functional programming on a dataflow architecture: Applications in real-time image processing

This paper presents a dataflow functional computer (DFFC) developed at the Etablissement Technique Central de l'Armement (ETCA) and dedicated to real-time image processing. Two types of data-driven processing elements, dedicated respectively to low-level and mid-level processings are integrated in a regular 3D array. The design of the DFFC relies on a close integration of the dataflow-architecture principles and the functional programming concept. An image processing algorithm, expressed with a syntax similar to that of functional programming (FP) is first converted into a dataflow graph. The nodes of this graph are real-time operators that can be implemented on the physical processors of the dataflow machine. This dataflow graph is then mapped directly onto the processor array. The programming environment includes a complete compilation stream from the FP specification to hardware implementation, along with a global operator database. Apart from being a research tool for real-time image processing, the DFFC may also be used to perform the automatic synthesis of autonomous vision automata from a high-level functional specification. An experimental system, including 1024 lowlevel custom dataflow processors and 12 T800 transputers, was built and can perform up to 50 billion operations/s. Several image processing algorithms were implemented on this system and run in real-time at digital video speed.     

Syntactical and semantical aspects of Faust

This paper presents some syntactical and semantical aspects of FAUST (Functional AUdio STreams), a programming language for real-time sound processing and synthesis. The programming model of FAUST combines two approaches: functional programming and block-diagrams composition. It is based on a block-diagram algebra. It as a well defined formal semantic and can be compiled into efficient C/C++ code.     

The Ada task system and real-time applications: an implementation schema

The Ada task system is critically evaluated from the point of view of real-time applications. Based on such an evaluation an abstract machine, supplying both an operational semantics and an implementation schema for it, is derived. Such a schema, depending on parameters, may supply a standard implementation following the Ada Reference Manual specifications, or may allow the user to implement ad hoc policies required by the time constraints of the specific application.     

Transducers are type-converters

The nature of a transducer is shown to be a mapping between representations (internal and external), analogous to the mapping between internal representations provided by typeconversion. Examples of this idea are given through programs in Ada and Modula.