Application of a Methodology for the Development and Validation of Reliable Process Control Software

This paper discusses the necessity of a good methodology for the development of reliable software, especialy with respect to the final software validation and testing activities. A formal specification development and validation methodology is proposed. This methodology has been applied to the development and validation of a pilot software, incorporating typical features of critical software for nuclear power plant safety protection. The main features of the approach indude the use of a formal specification language and the independent development of two sets of specifications. Analyses on the specifications consists of three-parts: validation against the functional requirements consistency and integrity of the specifications, and dual specification comparison based on a high-level symbolic execution technique. Dual design, implementation, and testing are performed. Automated tools to facilitate the validation and testing activities are developed to support the methodology. These includes the symbolic executor and test data generator/dual program monitor system. The experiences of applying the methodology to the pilot software are discussed, and the impact on the quality of the software is assessed.     

An Intelligent Tool to Support Requirements Analysis and Conceptual Design of Database Design

As an application of artificial intelligence and expert system technology to database design,this paper presents an intelligent design tool NITDT,which comprises a requirements specification language NITSL,a knowledge representation language NITKL,and an inference engine with uncertainty reasoning capability.NITDT now covers the requirements analysis and conceptual design of database design.However,it is possible to be integrated with another database design tool,NITDBA,developed also at NIT to become an integrated design tool supporting the whole process of database design.     

Task‐based conceptual graphs as a basis for automating software development

It is widely recognized that requirements engineering is a knowledge‐intensive process and cannot be dealt with using only a few general principles. Since knowledge plays a crucial role in software development, software engineers have to describe and organize various aspects of knowledge before the program can be written. A recent work by Robillard reveals that software development can be further improved by recognizing the relevant knowledge structures. In this paper, we propose the use of a task‐based conceptual graphs (TBCB) framework as a basis for automating software development. By structuring and operationalizing conceptual graphs, TBCG specifications can be transformed into executable programs automatically. To construct a conceptual model, task‐based specification methodology is used as the mechanism to structure the knowledge captured in conceptual models, whereas conceptual graphs are adopted as the formalism to express task‐based specifications and to provide a reasoning capability for the purpose of automation. Once task‐based graphs have been constructed and verified, a blackboard system will automatically transform TBCG specifications into a software system composed of database schemas, knowledge base, and user interfaces. A meeting scheduling system is used as an illustrative example to demonstrate our approach. © 2000 John Wiley & Sons, Inc.     

Issues in an inference platform for generating deductive knowledge: a case study in cultural heritage digital libraries using the CIDOC CRM

Most information retrieval research focuses collecting documents that match the same set of concepts. This study considers a more advanced problem, namely how to discover knowledge not contained in a single source from combined historical facts. By using a well-designed core ontology in the cultural domain (CIDOC CRM, ISO21127), this study discusses the requirement for a robust inference platform for real-life knowledge discovery and integration over distributed sources. The methodology and design are justified in detail through functional requirements for an inference service with the capability of inferring new knowledge from combinations of facts distributed over different sources. A number of critical issues for developing such a robust inference platform are identified, namely (1) systematic accumulation of common concepts and inference rules; (2) extending the ontology with metaclasses; (3) accumulation of factual and categorical knowledge; (4) incorporation of fuzzy inference into the inference engine, and (5) improvement of performance and scalability in the inference engine.     

Design of Ada Systems Yielding Reusable Components: An Approach Using Structured Algebraic Specification

Our experience with design of Ada¹ software has indicated that a methodology, based on formal algebra, can be developed which integrates the design and management of reusable components with Ada systems design. The methodology requires the use of a specification language, also based on formal algebra, to extend Ada's expressive power for this purpose. We show that certain requirements for the use of Ada packages which cannot be expressed in Ada can be expressed in algebraic specification languages, and that such specifications can then be implemented in Ada.     

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.     

基于SWRL的软件需求一致性验证方法

需求质量已经成为确保软件项目成功的一个重要因素,对复杂软件系统的需求进行检查和验证,是需求工程中非常重要的工作。在基于领域本体的需求获取和分析等相关工作基础上,提出了一种基于本体和语义规则的需求一致性验证方法,将自然语言描述的需求分解成若干结构良好的最小需求项,使用领域本体的概念模型对其进行形式化和结构化的表示。通过领域本体中的知识来映射需求语义,采用语义万维网规则语言（SWRL）来定义需求一致性验证的推理规则,并通过实例对此方法进行了分析和验证。     

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.     

Forming telecommunications software specifications from a service-driven model using enhanced software tools

Increasing diversity and sophistication among telecommunications customers has led to pressure on the telecommunications industry to give customer groups the capability to customize aspects of offered telecommunications services for their own particular needs. To offer such user-customizable services correctly, quickly, and cheaply, the telecommunications industry needs adequate techniques for transforming user requirements into software specifications and for realizing these software specifications with application code. In today's environment, several well-known software development life cycle processes exist for realizing software specifications; however, analogous techniques for transforming user requirements into explicit software specifications do not. This paper proposes a technique for transforming user requirements and then demonstrates its use on a sample telecommunications application. The technique creates a simulation environment that lets simulation users describe their application requirements and then determine the appropriate software specifications needed. The technique builds on aspects of a service-driven specification model and simulation software tools published earlier. Because the simulation environment derives from user requirements and produces software specifications, the proposed technique could represent the first phase of a service-driven software development life cycle process, eventually evolving from the nonservice-driven “requirements analysis” phase commonly used in practice today.     

A two‐step methodology to reduce requirement defects

Defects are introduced into a software product during every phase of software development. A major source of defects that is often overlooked is requirements generation. Requirement errors discovered in later phases of the software development process are the most costly to correct because all phases of software development are usually impacted. Requirement defects can be categorized into two main types: 1) specification generation errors; and 2) unwanted/unnecessary/incorrect user functionality. This experience report presents the results of incorporating a two‐step methodology which combines Operational Demonstrations of the user interface and Requirement Inspections on software requirement specifications. The two‐step methodology addresses and corrects both types of requirement defects. Results from this experience support the premise that cost reduction and quality improvement can be obtained using a combined Operational Demonstration and Requirement Inspection development methodology for software requirements.     

NEGATIVE AND POSITIVE EXPLANATIONS IN EXPERT SYSTEMS

A methodology for management of constraints in VLSI data bases is presented in this paper. The process of management is based on forma! mechanisms of attribute grammar theory. Examples of a modularized knowledge representation of a circuit at interconnection and logic levels based on attribute grammars illustrate the methodology. The ultimate goal and benefit of the proposed methodology is a well-defined development technique for VLSI design tools that will allow the user to generate a transformation system, a knowledge representation, and a system to manipulate this representation, all from a simple specification. In addition, context-dependent specifications at lower levels are automatically generated from the higher-level specifications.     

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.     

An application-oriented,optimization-based methodology for interactive design of engineering systems†

Motivated by a control system example, a new methodology is proposed for tackling optimal design of engineering systems. This methodology emphasizes designer's intuition and man-machine interaction. It includes a classification of specifications into various types and a scaling of specification space and parameter spaces based on the designer's knowledge of the particular application. An algorithm is proposed for solving the resulting constrained ‘minimax’ optimization problem and its convergence is proved. Finally, an application-oriented user front-end is presented. The methodology discussed in this paper has been implemented in the DELIGHT system and has been successfully used in various types of applications.     

Using abstraction and model checking to detect safety violations inrequirements specifications

Exposing inconsistencies can uncover many defects in software specifications. One approach to exposing inconsistencies analyzes two redundant specifications, one operational and the other property-based, and reports discrepancies. This paper describes a “practical” formal method, based on this approach and the SCR (software cost reduction) tabular notation, that can expose inconsistencies in software requirements specifications. Because users of the method do not need advanced mathematical training or theorem-proving skills, most software developers should be able to apply the method without extraordinary effort. This paper also describes an application of the method which exposed a safety violation in the contractor-produced software requirements specification of a sizable, safety-critical control system. Because the enormous state space of specifications of practical software usually renders direct analysis impractical, a common approach is to apply abstraction to the specification. To reduce the state space of the control system specification, two “pushbutton” abstraction methods were applied, one which automatically removes irrelevant variables and a second which replaces the large, possibly infinite, type sets of certain variables with smaller type sets. Analyzing the reduced specification with the model checker Spin uncovered a possible safety violation. Simulation demonstrated that the safety violation was not spurious but an actual defect in the original specification     

Semantic decoupling: reducing the impact of requirement changes

The continuous stream of requirements changes that often takes place during software development and can create major problems in the development process. This paper defines a concept we call semantic coupling that can be used during all the phases of a system specification and design to reduce the impact of changing requirements. Within the general framework of the intent specifications, traceability matrices representing the mappings between different abstraction levels are used to evaluate the sensitivity of a given design to requirement changes. The practicality of using the approach on real software is demonstrated using the specification of the control software for a NASA robot designed to service the heat-resistant tiles on the Space Shuttle.