• The KIPS Transactions:PartA
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• v.17A no.4
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• pp.173-180
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• 2010

To specify a formal semantics is to do a significant part for design, standardization and translation of programming languages. The existing studies of a formal semantics for Java have a weak point to describe a clear and practical semantics for an efficient translation. It is necessary to do research for a formal semantics to specify a static and dynamic semantics clearly in order to do an efficient translation. This paper presents the improved Action Equation that specifies a formal semantics for Java to extend the research using Action Equation. The Action Equation is a practical and accurate specification that describes object-oriented programming features and handles exceptions. The specified Action Equation is compared to other descriptions, in terms of readability, modularity, extensibility, and flexibility and then we verified that Action Equation is superior to other formal semantics.

• The KIPS Transactions:PartD
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• v.8D no.1
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• pp.99-104
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• 2001

As a plan to counteract solving software crisis, the technology that is called Component Based Software Engineering (CBSE or Componentware) is introsuced. Component Based Software Developement (CBSD) Processes as one of the technique among CBSE have been proposed. Component specification activities among CBSD Processed are necessary and important for generating feusable component. However, the existing CBSD processed can't ensure the correctness in requirements are reflected. In this paper, we propose that formal activities wgich specify component using formal specification language Z which is verified with the ability of analysis and logicality. The proposed activities are composed of 5 tasks and 12 subtasks. By presenting specific 19 products, it is also proposed that component specification activities which are the base of CBSD for reusing. The proposed activities are able to improve qualities of component through correctness and verification of requirements specification of users in the early step of component-based software process.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.4
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• pp.265-269
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• 2009

Formal specification plays important roles in guaranteeing software safety of safety-critical systems such as nuclear power plant's digital control systems. We had developed a technique [1] which synthesizes Function Block Diagram(FBD) programs from NuSCR formal requirements specifications, but it did not be used widely as it had no automatic tool support. FBD is one of the programming languages for Programmable Logic Controllers(PLC) based system. This paper introduces a CASE tool, NuSCRtoFBD, developed to automate the synthesis procedure. The CASE tool NuSCRtoFBD can reduce a number of errors occurred in the process of manual FBD programming.

• International Journal of Railway
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• v.5 no.2
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• pp.65-70
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• 2012

This paper introduced a novel railway system, Automatic Train Protection and Block (ATPB) briefly, which is proposed to improve the efficiency of existing regional train lines with low cost in Japan. The biggest superiority of ATPB system is a great use of universal and mature technologies, such as GPS and regular mobile telephone networks, so that there is nearly no increment of trackside equipments in the reconstruction. Then in order to guarantee the system safety, a formal model of ATPB is established and analyzed by formal method VDM++. Firstly, the specification is specified by VDM++ formally without ambiguity. Secondly, its internal consistency is proved by discharging the proof obligations. And finally, its satisfiability is checked by systematic testing, which executes specification and checks the outputs against corresponding inputs.

• Nuclear Engineering and Technology
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• v.54 no.5
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• pp.1635-1643
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• 2022

STPA (System-Theoretic Process Analysis) is a widely used safety analysis technique to identify UCAs (Unsafe Control Actions) resulting in potential losses. It is totally dependent on the experience and ability of analysts to construct an information model called Control Structures, upon which analysts try to identify unsafe controls between system components. This paper proposes a formal approach to support the manual identification of UCAs, effectively and systematically. It allows analysts to mechanically extract Process Model, an important element that makes up the Control Structures, from a formal requirements specification for a software controller. It then concisely constructs the contents of Context Tables, from which analysts can identify all relevant UCAs effectively, using a software fault tree analysis technique. The case study with a preliminary version of a Korean nuclear reactor protections system shows the proposed approach's effectiveness and applicability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.449-459
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• 2014

The proposed 2+1 view integrated metamodel defined formerly with a graphical class model can not be guaranteed the syntactic clarity and accuracy precisely for the metamodel due to the informal specification. This paper specifies the syntactic semantics formally for the 2+1 view integrated metamodel using Z and Object-Z and checks the accuracy of the metamodel with Z/Eves tool. The formal specification is expressed in Z and Object-Z schema separately for syntax and statics semantics of the 2+1 view integrated metamodel, which applying the converting rule between class model and Z/Object-Z. The accuracy of the Z specification for the metamodel is verified using Z/Eves tool, which can check the syntax, type, and domain of the Z specification. The transformation specification and checking of the 2+1 view integrated metamodel can help establish more accurate the syntactic semantics of its construct and check the accuracy of the metamodel.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.3
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• pp.337-344
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• 2000

In this paper, we define a Process Algebra ACSMR(Algebra of Communicating Shared Multiple Resources) for system specification and verification using multiple resources. ACSMR extends a concept of multiple resources in ACSR that is a branch of formal methods based on process algebra. We'll show that two specification and verification examples. One is the specification of system behavior in multiprocessor using EDF(Earliest-Deadline-First) which is a scheduling algorithm of a real-time system. The other is the specification of describing timing analysis and resources restriction in a super scalar processor using multiple ports registers.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5
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• pp.1426-1433
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• 2000

As distributed computing systems become popular, many modeling techniques and methods have been developed in specify the specification formally and verify the distributed/concurrent sytems. In spite of importance of communication in distributed object-oriented systems, specifying of communication method generally has not been emphasized in the design phase. One reason is due to the system designer misunderstanding, that is, a specification needs to be independent on the implementation. However, since defining communication pattern indistributed object-oriented systems is more serious than the required message passing method in the design phase. specifying the communication pattern is necessary instead of postponing until the implementation. In this paper, two formal specification techniques, temporal logic method and Petri nets method, for the communication in distributed systems are discussed. One is based on the temporal logic, which specifies the different patterns of primitive predicates. This method enable to define the underlying mechanism which can be interpreted as constraints. The Petri net method helps to specify the dynamic behavior of communicational patterns using the properties of Petri nets.

• Journal of KIISE:Software and Applications
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• v.33 no.12
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• pp.1008-1021
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• 2006

Product line engineering(PLE) is one of the recent and effective reuse approaches that enables developing a number of applications by instantiating a core asset. Elements of a core asset are product line architecture(PLA), component, and decision model. Among these elements, PLA is the key element since it defines the overall structure of the core asset. Although numerous PLE methodologies have been introduced, it is still unclear what should be the elements of a PLA and how to systematically instantiate it for specific applications. Formal specifications can play a key role in defining detailed and precise instantiation process. In this paper, we first present a meta model of PLA and show how to specify PLA in a formal language, Object-Z. Then, we propose instantiation rules using formal specification and those rules precisely define constraints for instantiating PLA. By applying the proposed formal specification, we believe PLA instantiation can be carried out precisely and correctly, yielding high quality software development.

• Journal of KIISE:Software and Applications
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• v.27 no.2
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• pp.120-133
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• 2000

Major obstruction of using formal methods for hybrid real-time systems in industry is the difficulty that engineers have in understanding and applying the quantitative methods in an abstract requirements phase. While formal methods technology in safety-critical systems can help increase confidence of software, difficulty and complexity in using them can cause another hazard. In order to overcome this obstruction, we propose a framework for qualitative requirements engineering of the hybrid real-time systems. It consists of a qualitative method for requirements specification, called QFM (Qualitative Formal Method), and a safety analysis method for the requirements based on a causality information, called CRSA (Causal Requirements Safety Analysis). QFM emphasizes the idea of a causal and qualitative reasoning in formal methods to reduce the cognitive burden of designers when specifying and validating the software requirements of hybrid safety systems. CRSA can evaluate the logical contribution of the software elements to the physical hazard of systems by utilizing the causality information that is kept during specification by QFM. Using the Shutdown System 2 of Wolsong nuclear power plants as a realistic example, we demonstrate the effectiveness of our approach.