Seo Ryong Koo

Software design specification and analysis technique (SDSAT) for the development of safety-critical systems based on a programmable logic controller (PLC)

This paper introduces a Software Design Specification and Analysis Technique (SDSAT) for safety-critical systems based on a Programmable Logic Controller (PLC). During software development phases, the design phase performs an important role in connecting the requirements phase and the implementation phase, and it is a process of translating software requirements into software structures. In this work, the Nuclear FBD-style Design Specification and analysis (NuFDS) approach was proposed for nuclear Instrumentation and Control (IC this tool is used specifically for generating software design specification and analysis for nuclear fields.

An effective technique for the software requirements analysis of NPP safety-critical systems, based on software inspection, requirements traceability, and formal specification

A thorough requirements analysis is indispensable for developing and implementing safety-critical software systems such as nuclear power plant (NPP) software systems because a single error in the requirements can generate serious software faults. However, it is very difficult to completely analyze system requirements. In this paper, an effective technique for the software requirements analysis is suggested. For requirements verification and validation (V&V) tasks, our technique uses software inspection, requirement traceability, and formal specification with structural decomposition. Software inspection and requirements traceability analysis are widely considered the most effective software V&V methods. Although formal methods are also considered an effective V&V activity, they are difficult to use properly in the nuclear fields as well as in other fields because of their mathematical nature. In this work, we propose an integrated environment (IE) approach for requirements, which is an integrated approach that enables easy inspection by combining requirement traceability and effective use of a formal method. The paper also introduces computer-aided tools for supporting IE approach for requirements. Called the nuclear software inspection support and requirements traceability (NuSISRT), the tool incorporates software inspection, requirement traceability, and formal specification capabilities. We designed the NuSISRT to partially automate software inspection and analysis of requirement traceability. In addition, for the formal specification and analysis, we used the formal requirements specification and analysis tool for nuclear engineering (NuSRS).

Development of a verification method for timed function blocks using ESDT and SMV

As programmable logic controllers (PLCs) are widely used in the digital instrumentation and control (I&C) systems of nuclear power plants (NPPs), the safety of PLC software has become the most important consideration. In this work, we propose a method to perform effective verification activities on the traceability analysis and the software design evaluation in the software design phase. In order to perform the traceability analysis between software requirement specification (SRS) written in a natural language and software design specification (SDS) written in function block diagram (FBD), this method uses extended- structured decision table (ESDT). ESDTs include information related to the traceability analysis from SRS and SDS, respectively. Through comparing with two ESDTs, an effective traceability analysis can be achieved. For the software design evaluation, we use model checking as a formal verification method. FBD-style design specification is translated into symbolic model verifier (SMV) input language and then the FBD-style design specification can be formally analyzed using SMV model checker.

A method of formal requirement analysis for NPP I&C systems based on UML modeling with software cost reduction

In this work, a formal requirement analysis method for Nuclear Power Plant (NPP) instrumentation and control (I&C) systems is suggested. This method uses unified modeling language (UML) for modeling a system visually and software cost reduction (SCR) for formally verifying the system. Since object-oriented methods enable us to analyze problems in terms of the objects in a real system, UML models are useful for understanding the problems and communicating with people involved in a project. In order to analyze problems more formally, SCR is used and the UML models are converted into SCR tabular notations. This work tries to acquire the flow-through from UML models to SCR specifications by suggesting additional syntactic extensions for UML notation and a converting procedure. The proposed method has been applied to a dynamic safety system (DSS) and inadequate core cooling monitoring system (ICCMS), which are parts of a NPP I&C system. Through these applications, some errors have been detected in the existing system requirements. Furthermore, in this work, through the comparison of our proposed method with the conventional inspection, we conclude that our method can complement the limitations of the inspection, which suffers from lack of detectability.

Software design specification and analysis technique for the safety critical software based on programmable logic controller (PLC)

This paper introduces the software design specification and analysis technique for the safety-critical system based on programmable logic controller (PLC). During software development phases, the design should perform an important role to connect between requirements phase and implementation phase as a process of translating problem requirements into software structures. In this work, the design specification features for nuclear instrumentation and control (I&C) software are suggested in a straight forward manner. It consists of four major specifications as follows; database, software architecture, system behavior, and PLC hardware configuration. Additionally, correctness, completeness, consistency, and traceability check techniques are also suggested for the formal design analysis.