Fuzzy logic as a basis for reusing task-based specifications

In this paper, we propose an approach to reusing requirements specification, called task-based specifications in conceptual graphs (TBCG). In TBCG, task-based specification methodology is used to serve as the mechanism to structure the knowledge captured in conceptual models, and conceptual graphs are adopted as the formalism to express requirements specification. TBCG provides several mechanisms to facilitate the reuse of formal specifications: a contextual retrieval mechanism to support context-sensitive specifications retrieval and incremental context acquisition, a graph matching mechanism to compute the similarity between two graphs based on the semantic match and fuzzy logic, and a paraphraser to serve as an explanation mechanism for the retrieval specifications. ©1999 John Wiley & Sons, Inc.     

一个支持规约获取的形式规约语言

该文介绍了形式规约语言LFC设计的一些主要方面，并通过例子说明了LFC的一些特色。形式规约语言LFC是为支持软件形式规约的获取工作而开发的。该语言以一种新的递归函数，即定义在上下文无关语言上的递归函数为基础，以上下文无关语言为数据类型，在语言级支持规约获取。LFC语言已被用作形式规约获取系统SAQ的一部分。使用表明，LFC是一个能力强、易使用的语言，适合软件形式规约获取之用，并且适合其它一些用途。     

On constructing communication protocols from component-based service specifications

Constructing communication protocols from component service specifications, each of which specifies a subfunction of the target protocol, enables efficient development of a large and complex communication protocol. Concerning this construction, related techniques have been already proposed: integration of component protocol specifications into a single protocol specification and transformation of service specifications to protocol specifications. However, the integration needs special knowledge of communication protocols, and the transformation requires that a large and complex service specification should be developed as input to produce the target protocol. In order to cope with these problems, this paper proposes a new method which at first integrates component service specifications into a single service specification, and then transforms the service specification into the target protocol by a protocol synthesis technique. The most important point of view is that component integration is performed at the service specification level rather than the protocol specification level. Additionally, we define a class of ‘well-formed’ service specification which ensures correctness of the target protocol. As a result, the integration and transformation can be efficiently executed in small state space without special knowledge of communication protocols. Finally, we have shown the effectiveness of the proposed method by constructing a part of the real-life OSI protocol FTAM.     

User interface specification with sequence diagrams: an application to the AIRBUS A380 Datalink system

The development of user interfaces for safety critical systems is driven by requirements specifications. Because user interface specifications are typically embedded within complex systems requirements specifications, they can be intractable to manage. Proprietary requirements specification tools do not support the user interface designer in modelling and specifying the user interface. In this paper, a new way of working with embedded user interface specifications is proposed, exploiting sequence diagrams with a hypertext structure for representing and retrieving use cases. This new tool concept is assessed through an application to the requirements specification for the Airbus A380 air traffic control Datalink system; engineers involved in the development of the Airbus cockpit used a prototype of the tool concept to resolve a set of user interface design anomalies in the requirements specification. The results of the study are positive and indicate the user interface to requirements specification tools which user interface designers themselves need.     

A framework for expressing the relationships between multiple viewsin requirements specification

Composite systems are generally comprised of heterogeneous components whose specifications are developed by many development participants. The requirements of such systems are invariably elicited from multiple perspectives that overlap, complement, and contradict each other. Furthermore, these requirements are generally developed and specified using multiple methods and notations, respectively. It is therefore necessary to express and check the relationships between the resultant specification fragments. We deploy multiple ViewPoints that hold partial requirements specifications, described and developed using different representation schemes and development strategies. We discuss the notion of inter-ViewPoint communication in the context of this ViewPoints framework, and propose a general model for ViewPoint interaction and integration. We elaborate on some of the requirements for expressing and enacting inter-ViewPoint relationships-the vehicles for consistency checking and inconsistency management. Finally, though we use simple fragments of the requirements specification method CORE to illustrate various components of our work, we also outline a number of larger case studies that we have used to validate our framework. Our computer-based ViewPoints support environment, The Viewer, is also briefly described     

Facilitating formal specification acquisition by using recursive functions on context-free languages

Although formal specification techniques are very useful in software development, the acquisition of formal specifications is a difficult task. This paper presents the formal specification language LFC, which is designed to facilitate the acquisition and validation of formal specifications. LFC uses context-free languages for syntactic aspect and relies on a new kind of recursive functions, i.e. recursive functions on context-free languages, for semantic aspect of specifications. Construction and validation of LFC specifications are machine-aided. The basic ideas behind LFC, the main aspects of LFC, and the use of LFC and illustrative examples are described.     

A Methodology for Constructing User-Oriented Requirements Specifications for Large-Scale Systems Using Electronic Hypermedia

requirements specifications are developed for large-scale systems, the final specification is usually an abstraction of the original requirements data into a text-based form that is often foreign to end-users. A method was developed for representing requirements through use of electronic multimedia. The resulting specification is capable of representing requirements and requirements data in a manner that is more representative of the real-world problem space than traditional specifications. This paper presents a method for incorporating multimedia exhibits, notably the results of rapid prototyping activities and animated simulation, into a requirements specification for large-scale C2I systems. To examine the effectiveness of the method, a multimedia requirements specification was developed based on an existing text specification for a real-world system. An experiment was also performed that showed the product of the methodology to be effective in increasing the understandability of the specification over that obtained from the text specification alone.     

电力应用系统与企业门户集成规范研究

电力行业信息化发展过程中出现了信息孤岛和数据不规范等问题,这些问题的解决已变得十分迫切。本文介绍电力公司身份管理与企业门户的集成接入规范,包括需要接入门户的应用系统在建设时所必须符合的要求和需要接入门户的应用系统在与门户集成时所必须遵守的规范。     

Bases for the development of LAST: a formal method for business software requirements specification

This paper proposes a possible approach to IS requirements specification. It relies on the application of standard (i.e. conventional) discrete mathematics, more precisely, it uses a fairly limited number of concepts from the fields of linear algebra and set theory (hence its name, LAST). The use of LAST for data definition and query–answer are discussed in some detail, given the data-rich quality of Business IS and the fact that a solid data-model is therefore essential to their specification. The proposed approach implies integration with other semiformal specification methods, two of the possibilities being integration with UML–OCL and with the Entity Relationship Model, which are discussed in this paper. Finally, mapping of LAST specifications to the Relational Model is also addressed; this possibility having an interest both, for (partial) implementation and for model simulation.     

Pushing requirements changes through to changes in specifications

Requirements changes can occur both during and after a phase of development for a variety of reasons, including error correction and feature changes. It is difficult and intensive work to integrate requirements changes made after specification is completed. Sequence-based specification was developed to convert ordinary functional software requirements into complete, consistent, and traceably correct specifications through a constructive process. Algorithms for managing requirements changes meet a very great need in field application of the sequence-based specification method. In this paper we propose to capture requirements changes as a series of atomic changes in specifications, and present polynomial-time algorithms for managing these changes. The algorithms are built into the tool support with which users are able to push requirements changes through to changes in specifications, maintain old specifications over time and evolve them into new specifications with the least amount of human interaction and rework. All our change algorithms are supported by rigorous mathematical formulation and proof of correctness. The application example is a safe controller. Software Quality Research Lab, Department of Electrical Engineering and Computer Science, University of Tennessee at Knoxville, http://www.cs.utk.edu/sqrl/     

Round-Trip Prototyping Based on Integrated Functional and User Interface Requirements Specifications

Requirements engineering in the new millennium is facing an increasing diversity of computerised devices comprising an increasing diversity of interaction styles for an increasing diversity of user groups. Thus the incorporation of user interface requirements into software requirements specifications becomes more and more mandatory. Validating these requirements specifications with hand-made, throw-away prototypes is not only expensive, but also bears the danger that validation results are not accurately fed back into the requirements specification. In this paper, we propose an enhancement of the requirements specification method SCORES for an explicit capturing of user interface requirements. The advantages of the approach are threefold. First, the user interface requirements specification is UML-compliant and integrated into the functional requirements specification. Second, prototypes for validation purposes can semi-automatically be generated. Third, the model-based generation of prototypes allows for ‘round-trip prototyping’ such that manual changes of the prototype during the validation process are automatically fed back into the requirements specification.     

Analogical reuse of requirements specifications: A computational model

Specifications of requirements for new software systems can be revised, refined, or completed in reference to specifications of requirements for existing similar systems. Although realized as a form of analogical problem solving, specification by reuse is not adequately supported by available computational models for detecting analogies. This is chiefly due to the following reasons: (1) It is assumed that specifications are expressed according to the same specification model and in a uniform representation scheme. (2) Additional information is needed for the detection of analogies, which is not contained in the specifications. (3) Performance scales poorly with the complexity of specifications. This article presents a computational model for detecting analogies, which addresses these issues to a certain extent. The application of the model in the specification of requirements by analogical reuse is demonstrated through an example, and its sensitivity to the representation of specifications is discussed. Finally, the results of a preliminary empirical evaluation of the model are reported.     

A formal approach to scenario integration

The scenario technique is an interesting approach for eliciting requirements. A formal approach to scenario generation has made it even more attractive. The next logical step is to integrate several scenarios into one single, consistent, specification. In this work, a mixed approach, involving formal and informal steps is proposed for performing this task. The system's formal specification is expressed as a finite state machine. The specifications of two interacting scenarios are integrated in a procedure involving formal and informal steps. Then several algorithms based on the properties of the model, are applied to detect three classes of errors: mistakes made by the analyst during the informal steps of the integration, inconsistencies between the scenarios, and incompleteness of both scenarios. Each algorithm detects the corresponding specification errors and in addition, suggests the corrections to apply. The formal techniques applied in this work could be the basis of a CASE tool for scenario‐based requirements engineering.     

A controlled experiment to evaluate how styles affect the understandability of requirements specifications

This paper presents a controlled experiment in which two different requirements specification styles (white-box and black-box) were compared concerning the understandability of two requirements specifications from the viewpoint of a customer. The results of the experiment confirm the common belief that black-box requirements specifications (e.g., documented with SCR) are easier to understand from a customer point of view than white-box specifications (e.g., documented with UML). Questions about particular functions and behavior of the specified system were answered faster and more correctly by the participants. This result suggests that using a black-box specification style when communicating with customers is beneficial.     

The impact of requirements changes on specifications and state machines

Requirements change both during and after a phase of development for a variety of reasons, including error correction and feature changes. Requirements change management is one of the most complex and difficult problems to deal with in requirements elicitation and tracking. It is generally not understood how a specific change propagates through the specification and into the code. In this paper we capture requirements changes as series of atomic changes in specifications. Using a rigorous specification method called sequence‐based specification, we propose a set of algorithms for managing all possible atomic requirements changes. The algorithms have been formulated within an axiom system for sequence‐based specification and proven for correctness. They have also been implemented in a prototype tool with which users are able to push requirements changes through to changes in specifications, maintain old specifications over time and evolve them into new specifications with the least amount of human interaction and rework. The approach of utilizing state machines to model and manage requirements changes guarantees strong evidence about the correctness and completeness of the proposed theory that will lead to more reliable software in the presence of change, especially with embedded systems and safety‐critical systems. The solution described is general enough for adoption by software and system developers, and well suited for incremental development. Copyright © 2008 John Wiley & Sons, Ltd.     

Specifying software quality with the extended ISO model

Specifying the quality of software products is a valuable addition to functional specification, clarifying product properties such as learnability and availability. Specifying such properties is considered difficult due to the different parties involved and the implicit nature of the requirements. The QUINT project gathered experience with product specification by means of the Extended ISO model: an extension to the ISO 9126 model of software quality. By defining indicators and specifying how they should be measured, quality specifications can make requirements explicit. Recommendations and pitfalls for composing a specification are grouped by the context in which quality specifications can be used.     

基于形式化监控的可信软件构造模型

传统的形式化方法和软件运行时监控都是提高软件可信性的有效途径,但存在监控需求表达能力不强及代码分散等问题。针对该问题,提出基于形式化监控的可信软件构造技术FM-TSPM,将形式化方法和运行时监控相结合,实现跨领域的方法融合。用形式化方法描述监控约束,根据监控约束生成方面监控代码,解决代码分散问题。采用AOP编织器将方面代码编织到目标系统中,构造出带监控能力的可信软件。     

ARINC 661规范及其应用开发研究

随着电子技术的飞速发展,航空电子的综合化程度和人机交互的要求都越来越高。但是由于行业规范缺失,航空电子器件接口各异,使得飞机座舱显示系统的开发发展缓慢,ARINC 661规范在这一背景下应运而生。经过近几年的修订和增补,该规范已相继被波音、空客、达索等公司采用,逐步发展成为行业标准。但国内相关方面的研究所见甚少,因而开展实现ARINC 661规范的研究工作显得尤为重要。本文首先对ARINC 661规范进行解读,给出实现ARINC 661规范的具体步骤,最后基于VAPS XT软件给出一个座舱仪表的设计示例。示例表明,本文提出的实现步骤是合理可行的,可为后续研究工作提供参考。     

Abstract Requirements Specification: A New Approach and Its Application

An abstract requirements specification states system requirements precisely without describing a real or a paradigm implementation. Although such specifications have important advantages, they are difficult to produce for complex systems and hence are seldom seen in the "real" programming world. This paper introduces an approach to producing abstract requirements specifications that applies to a significant class of real-world systems, including any system that must reconstruct data that have undergone a sequence of transformations. tions. It also describes how the approach was used to produce a requirements document for SCP, a small, but nontrivial Navy communications system. The specification techniques used in the SCP requirements document are introduced and illustrated with examples.