基于青鸟接口规约的全领域模型系统

现有的构件模型难以对领域的共性和变化性进行定义与描述,致使构件的粒度大小难以控制。基于常用的树形程序的特点,提出一种基于青鸟接口规约的全领域构件模型系统,整个系统由全领域构件模型及相应的二次加工工具系统组成。全领域构件模型能对领域中一族具有共性和变化性的描述进行代码实现;二次加工工具系统能对全领域构件进行二次加工,剔除构件中的冗余子模块。此全领域构件模型系统能够有效解决代码构件开发中经常遇到的构件的粒度大小问题。     

CAD支撑系统构件—软总线模型

在分析开放系统的特点和CAD支撑系统的具体需求的基础上,提出了CAD支撑系统构件-软总线模型（CSB模型）,在该模型中,图形功能模块和应用程序都被封装成为彼此独立且便于复用的构件,由软件总线实现集成,解释型和编译型两种类型程序语言开发的应用构件在系统中共存,并可在运行态动态增加/删除;同时,由总线适配器、解释器和应用服务代理组成的应用服务界面代理了构件之间复杂的通信过程,完成异构数据向同构数据的转换,使构件更专注于功能实现,根据CSB模型实现的一个开放的CAD支撑系统OpenDesign∧TM已经成功实现了产品化,应用实践证明,基于CSB模型的CAD支撑系统效率较高,具备比较好的互操作性和伸缩性,系统开放程度增加。     

Formal Reduction of Interfaces to Large-scale Process Control Systems

A formal methodology is proposed to reduce the amount of information displayed to remote human operators at interfaces to large-scale process control plants of a certain type.The reduction proceeds in two stages.In the first stage,minimal reduced subsets of components,which give full information about the state of the whole system,are generated by determining functional dependencies between components.This is achieved by using a temporal logic proof obligation to check whether the state of all components can be inferred from the state of components in a subset in specified situations that the human operator needs to detect,with respect to a finite state machine model of the system and other human operator behavior.Generation of reduced subsets is automated with the help of a temporal logic model checker.The second stage determines the interconnections between components to be displayed in the reduced system so that the natural overall graphical structure of the system is maintained.A formal definition of an aesthetic for the required subgraph of a graph representation of the full system,containing the reduced subset of components,is given for this purpose. The methodology is demonstrated by a case study.     

A component-based end-to-end simulation of the Linux file system

The Linux file system is designed with components utilizing a layered architecture. The upper components hide details of the lower components, and each layer presents unified and simple interfaces to the layers above and below. This design helps Linux to be flexible as well as to provide support for multiple types of storage devices. In this paper, this component architecture is used to develop a realistic simulation without having to model lower level details of the hardware layer or particular storage devices. A detailed simulation-based performance model of the Linux ext3 file system has been developed using Colored Petri Nets. The extensive validation study using the model obtains results that are close to the expected behavior of the real file system. The model demonstrates that file system parameters have a significant impact on the I/O performance.     

基于优先使用权的温贮备可修重试系统可靠性与期望成本模型

针对具有两种不同类型部件的温贮备可修系统,基于优先使用权规则,将部件的重试特性和不可靠修理设备引入系统,建立一种新的系统可靠性和成本模型.失效部件由一个不可靠修理设备维修,当正常的修理设备维修失效部件时会发生不完全故障,此时,它或以一定的概率立即被维修,或以一定的概率继续低效维修失效部件.在不完全故障下,修理设备有可能发生完全性故障,完全性故障后会立即被维修.鉴于维修环境的随机波动性,利用PH分布对修理设备的修理时间进行建模,这在一定程度上拓展了模型的适用性.通过概率讨论得到稳态下系统的一些主要性能指标,构建单位时间的总期望成本函数,并就总期望成本关于各参数的敏感性进行分析.通过数值实例展示系统参数对系统稳态性能指标和系统成本的影响,为系统可靠性设计者和决策者提供理论支撑和参考.     

基于组件的飞行控制系统软件设计方法

该文分析了无人直升机飞行控制系统软件实现要求。提出基于组件的程序设计方法开发此类软件，充分考虑模块的重用性，以组件为核心，每一组件单独开发与测试，然后按照一定的集成规则，分层、渐进地开发整个系统。组件之间的通信通过事件机制来实现，使得子系统之间的耦合减小，并且增加了系统的可靠性、灵活性和重用性。最后开发了飞行控制系统设计中的模型、参考模型和逆模型组件，并进行了仿真验证，结果表明这种设计方法将大大简化复杂控制系统的软件设计，方便系统软件的工程实现。     

Value‐based decision model for renewal processes in software maintenance

This work is based on a retrospective analysis of a renewal process applied to a very aged, highly degraded software system. Some parts of the results are generalized to define a method for determining the technical and economic qualities of software system components. The work also presents a decision model for identifying the most suitable renewal process to be applied, based on the quality of the components and the aims of the renewal process. With the model presented, decision‐making on the renewal process is specialized to each component of the software system, thus ensuring greater benefits from the process as a whole. The same model can be used to monitor software system quality decay and thus avoid the need to use the most costly renewal processes.     

Automatic inclusion of middleware performance attributes into architectural UML software models

Distributed systems often use a form of communication middleware to cope with different forms of heterogeneity, including geographical spreading of the components, different programming languages and platform architectures, etc. The middleware, of course, impact the architecture and the performance of the system. This paper presents a model transformation framework to automatically include the architectural impact and the overhead incurred by using a middleware layer between several system components. Using this framework, architects can model the system in a middleware-independent fashion. Accurate, middleware-aware models can then be obtained automatically using a middleware model repository. The actual transformation algorithm is presented in more detail. The resulting models can be used to obtain performance models of the system. From those performance models, early indications of the system performance can be extracted.     

Using semantic components to search for domain-specific documents: An evaluation from the system perspective and the user perspective

We seek to leverage an expert user's knowledge about how information is organized in a domain and how information is presented in typical documents within a particular domain-specific collection, to effectively and efficiently meet the expert's targeted information needs. We have developed the semantic components model to describe important semantic content within documents. The semantic components model for a given collection (based on a general understanding of the type of information needs expected) consists of a set of document classes, where each class has an associated set of semantic components. Each semantic component instance consists of segments of text about a particular aspect of the main topic of the document and may not correspond to structural elements in the document. The semantic components model represents document content in a manner that is complementary to full text and keyword indexing. This paper describes how the semantic components model can be used to improve an information retrieval system. We present experimental evidence from a large interactive searching study that compared the use of semantic components in a system with full text and keyword indexing, where we extended the query language to allow users to search using semantic components, to a base system that did not have semantic components. We evaluate the systems from a system perspective, where semantic components were shown to improve document ranking for precision-oriented searches, and from a user perspective. We also evaluate the systems from a session-based perspective, evaluating not only the results of individual queries but also the results of multiple queries during a single interactive query session.     

A software size model

A bottom-up approach to software size estimation is described. It first identifies factors affecting software size, thus obtaining size explanation equations, and then seeks suitable predictors based on those explanation factors which can be used for size estimation. The approach, or model, is bottom-up in that it sizes individual software components or modules first, and then obtains subsystem and system sizes by summing component sizes. Since components may have different purposes and characteristics, the model allows for the partitioning of system components into several different types, each component type having different size explanation and estimation equations. The partitioning is not fixed, but depends on the particular software development technology. The model is applied to several different software systems, including both business applications and systems programs     

一种基于BP组件的学习控制系统及其在倒立摆控制上的应用

给出了一个组件化方法设计学习控制系统的一个实例.学习控制系统建立在两个BP组件——BP模型和BP控制器的基础上,通过双通道反向学习的方法在控制过程中进行自我调整,适应控制对象的变化以及模型和控制器本身的不同条件.首先介绍了BP组件的接口和功能规范.然后建立基于BP组件的学习控制系统的组件化框架.最后给出一个基于BP组件的学习控制系统在倒立摆控制上的应用.     

CALPHAD应用于有机体系热力学相平衡/相图的计算

相图是一种化学图形,必须通过数学模型的方式才能实现其广泛的应用.而此前固-液平衡相图的计算多采用理想模型或经验模型,前者完全忽视了真实溶液的非理想性,后者的计算结果则可能是对相图完全不合理的预测.因此,为了充分考虑体系的非理想性以获得更为准确真实的相图,采用热力学模型,借助专业的金属及无机物材料的相图计算软件Thermo-Calc,设计实现了获得非理想有机体系中组分作用参数及平衡相图的软件计算方法.利用该计算方法,选择合理的热力学模型,成功地模拟出了二甲苯异构体系二元、三元及二氯苯异构体二元系的固-液平衡相图,模拟结果与文献的实验数据吻合程度较高,且相比于理想状态下的二甲苯三元系相图,正规溶液状态下的相图更能体现真实体系中组分间的作用对体系相平衡温度的影响.该软件计算方法具有较高的自动化程度,在实验数据非常有限的情况下,能够非常精确的模拟出各种无机或有机体系的相图及其它热力学性质,为化学热力学研究提供了一种新的、适用范围广、功能强大的研究手段.     

Certification of software components

Reuse is becoming one of the key areas in dealing with the cost and quality of software systems. An important issue is the reliability of the components, hence making certification of software components a critical area. The objective of this article is to try to describe methods that can be used to certify and measure the ability of software components to fulfil the reliability requirements placed on them. A usage modelling technique is presented, which can be used to formulate usage models for components. This technique will make it possible not only to certify the components, but also to certify the system containing the components. The usage model describes the usage from a structural point of view, which is complemented with a profile describing the expected usage in figures. The failure statistics from the usage test form the input of a hypothesis certification model, which makes it possible to certify a specific reliability level with a given degree of confidence. The certification model is the basis for deciding whether the component can be accepted, either for storage as a reusable component or for reuse. It is concluded that the proposed method makes it possible to certify software components, both when developing for and with reuse     

Distributed Software System Design Representation Using Modified Petri Nets

A model for representing and analyzing the design of a distributed software system is presented. The model is based on a modified form of Petri net, and enables one to represent both the structure and the behavior of a distributed software system at a desired level of design. Behavioral properties of the design representation can be verified by translating the modified Petri net into an equivalent ordinary Petri net and then analyzing that resulting Petri net. The model emphasizes the unified representation of control and data flows, partially ordered software components, hierarchical component structure, abstract data types, data objects, local control, and distributed system state. At any design level, the distributed software system is viewed as a collection of software components. Software components are externally described in terms of their input and output control states, abstract data types, data objects, and a set of control and data transfer specifications. They are interconnected through the shared control states and through the shared data objects. A system component can be viewed internally as a collection of subcomponents, local control states, local abstract data types, and local data objects.