Formal methods mainly aim to improve software reliability by systematic refinements and/or verifi... more Formal methods mainly aim to improve software reliability by systematic refinements and/or verifications between specifications and implementations in mathematical ways. However, they are not enough for validating whether the system functions meet the user’s requirements. We propose a combination of software prototyping and formal methods to address this problem. Our prototype provides desirable behaviors of system functions, and supports the generation of test cases by finding out input and output data related to the functions. This paper describes a case study for integrating a GUI-aided approach to constructing formal specifications and a testing-based verification of programs. Our research shows a demand for additional work on verifying external database accesses in automatic test case generation from formal specifications.
Component-based software development can help reduce time and cost by means of reusing software c... more Component-based software development can help reduce time and cost by means of reusing software components, but the quality of the software may not be ensured if the adopted components contain errors. The Structured Object-oriented Formal Language (SOFL) is a formal specification language that can be used for quality software development. This paper describes a development of desktop application software by connecting with several software components, and how it is developed using SOFL. We introduce how the requirements are analyzed through writing an informal specification and then refining it into a semi-formal specification. We also discuss how the design is carried out by constructing a formal specification in SOFL. Finally, we present the implementation and explain the details of a testing conducted for the quality assurance of the system.
2015 5th International Conference on IT Convergence and Security (ICITCS), 2015
In component based developments, precise specifications and rigorous verifications strongly suppo... more In component based developments, precise specifications and rigorous verifications strongly support to prevent unexpected failures caused by software components. For developing an application with third-party software components, formal methods provide effective ways to ensure the software quality. In this paper, we describe a development of web based dictionary system by connecting with several online resources, and how it is developed by using SOFL: a formal specification language and method. The requirements analysis is carried out by means of writing an informal specification and then refining into a semi-formal specification. The design specification is formally constructed using the formalized Data Flow Diagrams and the associated modules. We also discuss the implementation of the system and explain the details of a testing conducted for the quality assurance of the system.
To facilitate writing formal specifications in practice, we put forward a new GUI-aided approach ... more To facilitate writing formal specifications in practice, we put forward a new GUI-aided approach to formal specification construction for software design. By this approach, a GUI prototyping for the system is first carried out based on an informal requirements specification with the aim of improving the informal specification and then a formal design specification is constructed to precisely define the system architecture and functionality. We describe how a prototype GUI can be derived systematically based on the informal specification and discuss how the improved informal specification can be taken into account in constructing the formal design specification.
Structured Object-Oriented Formal Language and Method, 2016
The Structured Object-oriented Formal Language (SOFL) method is developed to overcome the disadva... more The Structured Object-oriented Formal Language (SOFL) method is developed to overcome the disadvantages of existing formal methods and provide effective techniques for writing formal specifications and carrying out verification and testing. Although it has been applied to system modeling and design in practical and research projects, SOFL has not been widely applied to the industrial software development systems because of the lack of efficient tool support. Aiming at improving the existing SOFL supporting tool and solving the problem that the formal specifications cannot be directly executed, this paper firstly analyzes the relationship between the structures of SOFL formal specifications and C# programs, and then discusses how module transformation and data type transformations are implemented. Finally, a testing is performed to ensure the reliability of the implemented software system.
This paper describes another application of the SOFL three-step specification approach in specify... more This paper describes another application of the SOFL three-step specification approach in specifying a railway interlocking system in industrial setting. We also explore the way of deriving hazard conditions from formal specifications, and propose a way to analyze the conditions for the assurance of the safety of the interlocking system in the early stage of the development. Our experience shows that SOFL is much more accessible by ordinary practitioners than other existing well-known formal methods and effective in helping practitioners deepen their understanding of the system details.
Structured Object-Oriented Formal Language and Method, 2019
Pair programming is one of the promising techniques advocated in agile development paradigm, but ... more Pair programming is one of the promising techniques advocated in agile development paradigm, but it tends to be more costly than one person-based programming and to lack a rigorous principle for governing the cooperation of the two programmers. In this paper, we put forward a novel technique called Software Construction Monitoring and Predicting to study an intelligent and automatic approach to human-machine pair programming. Its aim is to automatically, dynamically monitor the process of software construction for fault detection and to predict the possible future contents of the software towards its error-free completion. We describe the theoretical foundation and frameworks for Software Construction Monitoring (SCM) and Software Construction Predicting (SCP), respectively. We also discuss how SCMP can support the Specification-Based programming paradigm. Finally, we use simple examples to illustrate how SCM and SCP can be supported.
Proceedings. Ninth IEEE International Conference on Engineering of Complex Computer Systems
Abstract Software review is an effective means to enhance the quality of software systems. Howeve... more Abstract Software review is an effective means to enhance the quality of software systems. However, traditional review methods emphasize the importance of the way to organize reviews and rely on the quality of the reviewers' experience and personal skills. In this paper we propose a new approach to rigorously reviewing programs based on their formal specifications. The fundamental idea of the approach is to use a formal specification as a standard to check whether all the required functions and properties in the specification are ...
When developing a formal specification for a software project using the SOFL three-step modeling ... more When developing a formal specification for a software project using the SOFL three-step modeling approach, it is essential to ensure the conformance relation between every two level specifications. Inspection is an important technique to verify the specifications. In this paper, we describe an inspection method through building traceability for rigorously verifying the conformance relation. The method consists of two steps: (1) traceability establishment and (2) inspection of the target specifications based on the built traceability. We also provide some inspection strategies such as checklists based on SOFL features to help the inspector find errors and keep the consistency. Our tool provides a convenient interface to separate components in different specifications and save their relationships to keep the consistency. We describe the design and implementation of our supporting tool in this thesis. A case study to inspect the specifications of a travel plan booking system is given to show how the proposed method can be applied in practice.
International Journal of Software Engineering and Knowledge Engineering, 2011
Software risk comes mainly from its poor reliability, but how to effectively achieve high reliabi... more Software risk comes mainly from its poor reliability, but how to effectively achieve high reliability still remains a challenge. This paper puts forward a framework for systematically integrating formal specification, review, and testing, and shows how it can be applied to effectively eliminate errors in the major phases of software development process to enhance software reliability. In this framework, requirements errors can be removed and missing requirements can be identified by formalizing requirements into formal specifications whose validity can be ensured by rigorous review. The valid specification can then be used as a firm foundation for implementation and for rigorous inspection, testing, and walkthrough of the implemented program. We discuss how formalization, review, and testing work together at different levels of software development to improve software reliability through detecting and removing errors in documentation.
Proceedings of the 30th annual Southeast regional conference on - ACM-SE 30, 1992
As formal methods are increasingly used in the development of industrial scale software systems, ... more As formal methods are increasingly used in the development of industrial scale software systems, there is a growing awareness of the need to integrate the formal notations with existing structured software development methods. In order to make requirements analysis both comprehensible and rigorous, a User-Friendly Formal Requirements Specification Method is proposed in this paper by combining and extending DeMarco data flow diagrams with VDM (Vienna Development Method). The specifications produced using this method possess good readability, a well-designed structuring mechanism and precise semantics. The significant progress presented in this paper is to develop a verified analysis approach based on the concept of consistency checking for guaranteeing the correctness of analysis steps.
Innovations in Systems and Software Engineering, 2010
The real-time process calculus Timed CSP is capable of expressing properties such as deadlock-fre... more The real-time process calculus Timed CSP is capable of expressing properties such as deadlock-freedom and real-time constraints. It is therefore well-suited to model and verify embedded software. However, proofs about Timed CSP specifications are not ensured to be correct since comprehensive machine-assistance for Timed CSP is not yet available. In this paper, we present our formalization of Timed CSP in the Isabelle/HOL theorem prover, which we have formulated as an operational coalgebraic semantics together with bisimulation equivalences and coalgebraic invariants. This allows for semi-automated and mechanically checked proofs about Timed CSP specifications. Mechanically checked proofs enhance confidence in verification because corner cases cannot be overlooked. We additionally apply our formalization to an abstract specification with real-time constraints. This is the basis for our current work, in which we verify a simple real-time operating system deployed on a satellite. As this operating system has to cope with arbitrarily many threads, we use verification techniques from the area of parameterized systems for which we outline their formalization.
Formal specification has proved to be an effective technique for precisely defining software func... more Formal specification has proved to be an effective technique for precisely defining software functionality, but validating it against the user's requirements still remains a challenge. In this paper, we propose a novel and practical review approach that utilizes specification animation and trace links to support the reviewing of formal specifications for their validation. The scenario-based animation method dynamically presents the specification to the reviewer by means of "executing" it in a step-by-step manner. It is adopted as a reading technique to guide the reviewer to read the specification and provides him with clear review targets. The trace links that connect the specification to the user's original requirements supply the reviewer with necessary information for determining whether defects are found. We first explain the scenario-based animation and trace links respectively and then propose a group of criteria for validating the formal specification. A case study is described to illustrate the review process at the end of the paper.
Proceedings. 2nd IEEE Workshop on Industrial Strength Formal Specification Techniques
This paper describes an application of the formal engineering method SOFL (Structured-Object-base... more This paper describes an application of the formal engineering method SOFL (Structured-Object-based-Formal Language) to specifying a realistic railway crossing controller for potential use in industry. As the railway crossing controller is a safety-critical and real-time system, this application demonstrates the capability of SOFL for developing safety-critical and real-time systems and provides a foundation for implementing such a software controller in practice. It also shows that appropriate integration of structured methods with graphical notation, formal notation, and natural language oers a good readability and traceability as well as an eective mechanism for reducing complexity of systems.
Formal methods mainly aim to improve software reliability by systematic refinements and/or verifi... more Formal methods mainly aim to improve software reliability by systematic refinements and/or verifications between specifications and implementations in mathematical ways. However, they are not enough for validating whether the system functions meet the user’s requirements. We propose a combination of software prototyping and formal methods to address this problem. Our prototype provides desirable behaviors of system functions, and supports the generation of test cases by finding out input and output data related to the functions. This paper describes a case study for integrating a GUI-aided approach to constructing formal specifications and a testing-based verification of programs. Our research shows a demand for additional work on verifying external database accesses in automatic test case generation from formal specifications.
Component-based software development can help reduce time and cost by means of reusing software c... more Component-based software development can help reduce time and cost by means of reusing software components, but the quality of the software may not be ensured if the adopted components contain errors. The Structured Object-oriented Formal Language (SOFL) is a formal specification language that can be used for quality software development. This paper describes a development of desktop application software by connecting with several software components, and how it is developed using SOFL. We introduce how the requirements are analyzed through writing an informal specification and then refining it into a semi-formal specification. We also discuss how the design is carried out by constructing a formal specification in SOFL. Finally, we present the implementation and explain the details of a testing conducted for the quality assurance of the system.
2015 5th International Conference on IT Convergence and Security (ICITCS), 2015
In component based developments, precise specifications and rigorous verifications strongly suppo... more In component based developments, precise specifications and rigorous verifications strongly support to prevent unexpected failures caused by software components. For developing an application with third-party software components, formal methods provide effective ways to ensure the software quality. In this paper, we describe a development of web based dictionary system by connecting with several online resources, and how it is developed by using SOFL: a formal specification language and method. The requirements analysis is carried out by means of writing an informal specification and then refining into a semi-formal specification. The design specification is formally constructed using the formalized Data Flow Diagrams and the associated modules. We also discuss the implementation of the system and explain the details of a testing conducted for the quality assurance of the system.
To facilitate writing formal specifications in practice, we put forward a new GUI-aided approach ... more To facilitate writing formal specifications in practice, we put forward a new GUI-aided approach to formal specification construction for software design. By this approach, a GUI prototyping for the system is first carried out based on an informal requirements specification with the aim of improving the informal specification and then a formal design specification is constructed to precisely define the system architecture and functionality. We describe how a prototype GUI can be derived systematically based on the informal specification and discuss how the improved informal specification can be taken into account in constructing the formal design specification.
Structured Object-Oriented Formal Language and Method, 2016
The Structured Object-oriented Formal Language (SOFL) method is developed to overcome the disadva... more The Structured Object-oriented Formal Language (SOFL) method is developed to overcome the disadvantages of existing formal methods and provide effective techniques for writing formal specifications and carrying out verification and testing. Although it has been applied to system modeling and design in practical and research projects, SOFL has not been widely applied to the industrial software development systems because of the lack of efficient tool support. Aiming at improving the existing SOFL supporting tool and solving the problem that the formal specifications cannot be directly executed, this paper firstly analyzes the relationship between the structures of SOFL formal specifications and C# programs, and then discusses how module transformation and data type transformations are implemented. Finally, a testing is performed to ensure the reliability of the implemented software system.
This paper describes another application of the SOFL three-step specification approach in specify... more This paper describes another application of the SOFL three-step specification approach in specifying a railway interlocking system in industrial setting. We also explore the way of deriving hazard conditions from formal specifications, and propose a way to analyze the conditions for the assurance of the safety of the interlocking system in the early stage of the development. Our experience shows that SOFL is much more accessible by ordinary practitioners than other existing well-known formal methods and effective in helping practitioners deepen their understanding of the system details.
Structured Object-Oriented Formal Language and Method, 2019
Pair programming is one of the promising techniques advocated in agile development paradigm, but ... more Pair programming is one of the promising techniques advocated in agile development paradigm, but it tends to be more costly than one person-based programming and to lack a rigorous principle for governing the cooperation of the two programmers. In this paper, we put forward a novel technique called Software Construction Monitoring and Predicting to study an intelligent and automatic approach to human-machine pair programming. Its aim is to automatically, dynamically monitor the process of software construction for fault detection and to predict the possible future contents of the software towards its error-free completion. We describe the theoretical foundation and frameworks for Software Construction Monitoring (SCM) and Software Construction Predicting (SCP), respectively. We also discuss how SCMP can support the Specification-Based programming paradigm. Finally, we use simple examples to illustrate how SCM and SCP can be supported.
Proceedings. Ninth IEEE International Conference on Engineering of Complex Computer Systems
Abstract Software review is an effective means to enhance the quality of software systems. Howeve... more Abstract Software review is an effective means to enhance the quality of software systems. However, traditional review methods emphasize the importance of the way to organize reviews and rely on the quality of the reviewers' experience and personal skills. In this paper we propose a new approach to rigorously reviewing programs based on their formal specifications. The fundamental idea of the approach is to use a formal specification as a standard to check whether all the required functions and properties in the specification are ...
When developing a formal specification for a software project using the SOFL three-step modeling ... more When developing a formal specification for a software project using the SOFL three-step modeling approach, it is essential to ensure the conformance relation between every two level specifications. Inspection is an important technique to verify the specifications. In this paper, we describe an inspection method through building traceability for rigorously verifying the conformance relation. The method consists of two steps: (1) traceability establishment and (2) inspection of the target specifications based on the built traceability. We also provide some inspection strategies such as checklists based on SOFL features to help the inspector find errors and keep the consistency. Our tool provides a convenient interface to separate components in different specifications and save their relationships to keep the consistency. We describe the design and implementation of our supporting tool in this thesis. A case study to inspect the specifications of a travel plan booking system is given to show how the proposed method can be applied in practice.
International Journal of Software Engineering and Knowledge Engineering, 2011
Software risk comes mainly from its poor reliability, but how to effectively achieve high reliabi... more Software risk comes mainly from its poor reliability, but how to effectively achieve high reliability still remains a challenge. This paper puts forward a framework for systematically integrating formal specification, review, and testing, and shows how it can be applied to effectively eliminate errors in the major phases of software development process to enhance software reliability. In this framework, requirements errors can be removed and missing requirements can be identified by formalizing requirements into formal specifications whose validity can be ensured by rigorous review. The valid specification can then be used as a firm foundation for implementation and for rigorous inspection, testing, and walkthrough of the implemented program. We discuss how formalization, review, and testing work together at different levels of software development to improve software reliability through detecting and removing errors in documentation.
Proceedings of the 30th annual Southeast regional conference on - ACM-SE 30, 1992
As formal methods are increasingly used in the development of industrial scale software systems, ... more As formal methods are increasingly used in the development of industrial scale software systems, there is a growing awareness of the need to integrate the formal notations with existing structured software development methods. In order to make requirements analysis both comprehensible and rigorous, a User-Friendly Formal Requirements Specification Method is proposed in this paper by combining and extending DeMarco data flow diagrams with VDM (Vienna Development Method). The specifications produced using this method possess good readability, a well-designed structuring mechanism and precise semantics. The significant progress presented in this paper is to develop a verified analysis approach based on the concept of consistency checking for guaranteeing the correctness of analysis steps.
Innovations in Systems and Software Engineering, 2010
The real-time process calculus Timed CSP is capable of expressing properties such as deadlock-fre... more The real-time process calculus Timed CSP is capable of expressing properties such as deadlock-freedom and real-time constraints. It is therefore well-suited to model and verify embedded software. However, proofs about Timed CSP specifications are not ensured to be correct since comprehensive machine-assistance for Timed CSP is not yet available. In this paper, we present our formalization of Timed CSP in the Isabelle/HOL theorem prover, which we have formulated as an operational coalgebraic semantics together with bisimulation equivalences and coalgebraic invariants. This allows for semi-automated and mechanically checked proofs about Timed CSP specifications. Mechanically checked proofs enhance confidence in verification because corner cases cannot be overlooked. We additionally apply our formalization to an abstract specification with real-time constraints. This is the basis for our current work, in which we verify a simple real-time operating system deployed on a satellite. As this operating system has to cope with arbitrarily many threads, we use verification techniques from the area of parameterized systems for which we outline their formalization.
Formal specification has proved to be an effective technique for precisely defining software func... more Formal specification has proved to be an effective technique for precisely defining software functionality, but validating it against the user's requirements still remains a challenge. In this paper, we propose a novel and practical review approach that utilizes specification animation and trace links to support the reviewing of formal specifications for their validation. The scenario-based animation method dynamically presents the specification to the reviewer by means of "executing" it in a step-by-step manner. It is adopted as a reading technique to guide the reviewer to read the specification and provides him with clear review targets. The trace links that connect the specification to the user's original requirements supply the reviewer with necessary information for determining whether defects are found. We first explain the scenario-based animation and trace links respectively and then propose a group of criteria for validating the formal specification. A case study is described to illustrate the review process at the end of the paper.
Proceedings. 2nd IEEE Workshop on Industrial Strength Formal Specification Techniques
This paper describes an application of the formal engineering method SOFL (Structured-Object-base... more This paper describes an application of the formal engineering method SOFL (Structured-Object-based-Formal Language) to specifying a realistic railway crossing controller for potential use in industry. As the railway crossing controller is a safety-critical and real-time system, this application demonstrates the capability of SOFL for developing safety-critical and real-time systems and provides a foundation for implementing such a software controller in practice. It also shows that appropriate integration of structured methods with graphical notation, formal notation, and natural language oers a good readability and traceability as well as an eective mechanism for reducing complexity of systems.
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