Extension of Pascal by coroutines and its application to quasi-parallel programming and simulation

This paper describes an extension of Pascal by coroutines as a basic tool to make quasi-parallel programming possible. This extension is acheived by predefined procedures, i.e. by semantical means without modification of the syntax of the language. Process and simulation concepts are developed entirely in the extended Pascal. These concepts are suited for quasi-parallel programming and for process-oriented simulation of discrete-event systems. The presented simulation system is easy to implement, it is flexible and modifiable. It retains the powerful facilities and the portability and availability of Pascal.     

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.     

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.     

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.     

面向对象软件系统的一种度量方法及其应用

在面向对象系统分析和设计过程中，类的设计质量直接关系到软件系统质量。首先对类之间的关系进行了分析、说明和定义，并分为横向关系和纵向关系，给出了横向关系和纵向关系度量与质量评价，并在此基础上给出了改善类设计质量的方法。     

A design perspective of mechanical function and its object-oriented representation scheme

The purpose of this paper is to present a functional schema which can be used to develop computer tools to assist designers during the early stages of the mechanical product design process. The schema is based on an analysis of the meaning of function. five main types of mechanical function are described: performance, assembly, manufacturing, marketing and maintenance. The paper focuses on the specification and representation of performance functions. These are defined using a natural language, which is an extension of the verb-noun pair technique. Three levels of performance functions are identified: overall, embodiment and geometric. The relationship between these levels of functions and the physical structures required to implement them is discussed in detail. An architecture to implement the schema using object-oriented technology is described. A research prototype based on this architecture has been developed in the programming language Incr Tcl/Tk.     

A software complexity model of object-oriented systems

A model for the emerging area of software complexity measurement of OO systems is required for the integration of measures defined by various researchers and to provide a framework for continued investigation. We present a model, based in the literature of OO systems and software complexity for structured systems. The model defines the software complexity of OO systems at the variable, method, object, and system levels. At each level, measures are identified that account for the cohesion and coupling aspects of the system. Users of OO techniques perceptions of complexity provide support for the levels and measures.     

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.     

蛋白质突变仿真&虚拟筛选系统的开发和应用

筛选因过程复杂造成费钱费时费力,成为定向进化的瓶颈。因此,开发出蛋白质突变仿真&虚拟筛选系统,以部分替代实验筛选,提高筛选效率,具有十分重要的意义。利用对字符串的随机替换来模仿蛋白质序列的突变,通过加权二肽组成、偏最小二乘回归等数学模型对产生的蛋白质序列进行筛选。开发的蛋白质突变仿真&虚拟筛选系统软件,可以部分替代实验筛选。软件在WINDOWS XP及DotNetFramework 2.0下运行稳定,计算速度快,拟合结果良好,基本可以满足数据处理的需要。软件的参数灵活可调,能够输出各种数据,可以方便分析验证,也可与其它软件整合进行数据分析以达到研究目的。     

A relationship-based and object-oriented software for monitoring management during geotechnical excavation

The efficient management of monitoring data is necessary for large geotechnical engineering projects. The development of an information management, prediction and warning software system for geotechnical monitoring is presented in this study. Seven categories of property objects that describe the hierarchical relationships among the monitoring objects, as well as two objects that represent and manage the construction progress, are proposed based on the requirements of geotechnical monitoring, data flow and the monitoring objectives of the site. The corresponding data structure and database were established using the object-oriented method in the Visual C++ environment. The software integrated various types of information and document management schemes, including data input and processing, CAD drawing visualisation, data modelling and prediction, as well as an early warning function. The applied case studies indicate that the software system is highly flexible and reliable and can be widely applied to monitor the sites of various geotechnical construction projects, such as tunnels, underground caverns, slopes and foundation pits.     

时间驱动仿真及其在宽带网络仿真中的应用

宽带网络的主要设备是宽带交换设备 ,如高性能路由器 ,交换机等 .因此 ,对宽带计算机网络的仿真 ,主要是对网络的宽带交换设备进行仿真 ,其关键是仿真速度问题 .本文针对计算机网络离散系统 ,提出了基于时间驱动的适合于离散系统的仿真算法 ,并与离散事件驱动仿真算法进行比较     

面向对象开发DeltaV系统仿真支撑环境

DeltaV是一种管理FFCS(Foundation Fieldbus Control System)的软件系统，用面向对象技术开发其仿真支撑环境，建立了流程图组态类库，包括设备类、仪表类、物流类等等，每一类都定义有如类型、种类、方向、位置、颜色、标记等属性，同时定义了对象的建立、标记、移动和缩放等方法，可灵活地增减类库成员和改变属性和方法。     

An application of coroutines and backtracking in interactive systems

A software structure well-suited for the programming of interactive recognition and translation systems is described. This structure makes use of coroutines and backtracking in a highly coordinated and integrated fashion. A set of coroutine and backtracking primitives that supports this approach is defined. An example of the use of this approach is given.     

A methodology to assess the impact of design patterns on software quality

Context

Software quality is considered to be one of the most important concerns of software production teams. Additionally, design patterns are documented solutions to common design problems that are expected to enhance software quality. Until now, the results on the effect of design patterns on software quality are controversial.

Aims

This study aims to propose a methodology for comparing design patterns to alternative designs with an analytical method. Additionally, the study illustrates the methodology by comparing three design patterns with two alternative solutions, with respect to several quality attributes.

Method

The paper introduces a theoretical/analytical methodology to compare sets of “canonical” solutions to design problems. The study is theoretical in the sense that the solutions are disconnected from real systems, even though they stem from concrete problems. The study is analytical in the sense that the solutions are compared based on their possible numbers of classes and on equations representing the values of the various structural quality attributes in function of these numbers of classes. The exploratory designs have been produced by studying the literature, by investigating open-source projects and by using design patterns. In addition to that, we have created a tool that helps practitioners in choosing the optimal design solution, according to their special needs.

Results

The results of our research suggest that the decision of applying a design pattern is usually a trade-off, because patterns are not universally good or bad. Patterns typically improve certain aspects of software quality, while they might weaken some other.

Conclusions

Concluding the proposed methodology is applicable for comparing patterns and alternative designs, and highlights existing threshold that when surpassed the design pattern is getting more or less beneficial than the alternative design. More specifically, the identification of such thresholds can become very useful for decision making during system design and refactoring.     

A modified Yule process to model the evolution of some object-oriented system properties

We present a model based on the Yule process, able to explain the evolution of some properties of large object-oriented software systems. We study four system properties related to code production of four large object-oriented software systems - Eclipse, Netbeans, JDK and Ant. The properties analysed, namely the naming of variables and methods, the call to methods and the inheritance hierarchies, show a power-law distribution as reported in previous papers for different systems. We use the simulation approach to verify the goodness of our model, finding a very good correspondence between empirical data of subsequent software versions, and the prediction of the model presented.     

Applying simulation and design of experiments to the embedded software testing process

This paper presents some original solutions with regard to the deployment of the U.S. Department of Defense Simulation, Test and Evaluation Process (DoD STEP), using an automated target tracking radar system as a case study. Besides the integration of modelling and simulation, to form a model‐based approach to the software testing process, the number of experiments, i.e. test cases, have been dramatically reduced by applying an optimized design‐of‐experiment plan and an orthogonal array‐based robust testing methodology. Also, computer‐based simulation at various abstraction levels of the system/software under test can serve as a test oracle. Simulation‐based (stochastic) experiments, combined with optimized design‐of‐experiment plans, in the case study have shown a minimum productivity increase of 100 times in comparison to current practice without DoD STEP deployment. Copyright © 2004 John Wiley & Sons, Ltd.     

离散系统快速递推仿真算法及其在柔性制造系统中的应用

本文对具有中央服务台形式,队列均为FCFS服务规则,不同顾客类不同路径和不同服务速率的闭网络进行了研究。文中引入多变量排队网络理论建立了一类离散事件系统仿真模型,提出一快速递推算法,该算法计算量小并应用于实际问题。     

High-accuracy simulation of orbital dynamics: An object-oriented approach

The use of Keplerian or Equinoctial parameters instead of Cartesian coordinates as state variables in object-oriented spacecraft models is introduced in this paper. The rigid body model of the standard MultiBody library is extended by adding transformation equations from Keplerian or Equinoctial parameters to Cartesian coordinates, and by setting the former as preferred states, instead of the latter. The remaining parts of the model are left untouched, thus ensuring maximum re-usability of the model itself. The results shown in the paper demonstrate the superior accuracy and speed of computation both in the case of a point-mass gravity field, and in the case of more accurate gravity field models.