• International Journal of Railway
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• 제2권3호
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• pp.99-106
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• 2009

Checks and tests before putting safety facilities into service as well as the results of these tests are essential, time consuming and may show great variations between each other. Economic constraints and the increasing complexity associated with the development of computerized tools tend to limit the capacity of the classic approval process (manual or automatic). A reduction of the validation cover rate could result in practice. This is not compatible with the French national plan to renew the interlocking systems of the national network. The method and the tool presented in this paper makes it possible to formally validate new computerized systems or evolutions of existing French interlocking systems with real-time functional interpreted Petri nets. The aim of our project is to provide SNCF with a method for the formal validation of French interlocking systems. A formal proof method by assertion, which is applicable to industrial automation equipment such as interlocking systems, and which covers equally the specification and its real software implementation, is presented in this paper. With the proposed method we completely verify that the system follows all safety properties at all times and does not show superfluous conditions: it replaces all the indoor checks (not the outdoor checks). The advantages expected are a significant reduction of testing time and of the related costs, an increase of the test coverage rate, an answer to the new demand of railway infrastructure maintenance engineering to modify and validate computerized interlocking systems. Formal methods mastery by infrastructure engineers are surely a key to prove that more safety is not necessarily more expensive.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.2489-2491
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• 2005

Currently, Programmable Logic Contorller(PLC) uses Real Time Operation System(RTOS) as basic OS. RTOS executes defined results as to defined time. General features of RTOS emphasize the priority in each task, high-speed process of external interrupt, task scheduling, synchronization in task, the limitation of memory capacity. For safety critical placement, PLC software needs Verification and Validation(V&V). For example, nuclear power plant. In this paper, PLC RTOS is verified by formal methods. Particularly, formal method V&V uses verification tool called 'STATEMATE', and shows the results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.920-923
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• 2002

In this paper, we propose Class Diagram With Constraints (CDWC) as an object oriented modeling technique which makes validation possible in software development. CDWC is a simple and basic model for the object oriented analysis, and has a reasonable strictness for software developers. CDWC consists of class diagrams and constraints (invariant and pre/post conditions), using UML and a subset of OCL.. We introduce a method of validation of CDWC using the verification technique of algebraic formal specification language CafeOBJ.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제6권2호
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• pp.161-172
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• 2000

본 논문에서는 ForTIA라 불리는 LOTOS 지원도구의 개발을 소개한다. ISO 표준 정형 명세 언어인 LOTOS는 사용자의 요구사항이나 시스템 모형을 추상화하여 정형적으로 작성할 수 있도록 함으로써 구현에 이르기 전에 명세 상에서 시스템을 확인 및 검증할 수 있게 한다. ForTIA는 LOTOS 정형기법이 산업계에 적용될 수 있도록 확인 위주의 경량 정형기법 기능을 제공한다. ForTIA의 핵심적인 기능은 명세 시뮬레이션과 C++ 코드 생성이다. 시뮬레이션은 편리하고 직관적인 상호작용을 위한 트리 기반의 시각적 명세확인 메카니즘을 제공하고 C++코드생성은 LOTOS로부터 완전한 C++ 코드를 생성하여 시스템의 실제 구현에 이용될 수 있도록 한다.

• 한국통신학회논문지
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• 제29권3B호
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• pp.360-374
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• 2004

OSPF 프로토콜은 가장 보편적으로 사용되고 있는 Interior Gateway Routing Protocol 이다. 그러므로, 초고속 라우터의 동작의 신뢰성 확보를 위해, OSPF 프로토콜의 상호운용성과 안전성의 보장은 중요하다. 본 논문에서는 OSPF 라우팅 프로토콜의 표준 문서를 분석하여, 프로토콜 동작들을 대수 정형 방법을 사용하여 상세 설계 수준으로 명세하고, OSPF 프로토콜의 가용한 원천코드를 참조하여, 표준에 명확하게 명세되지 않은 좀더 상세한 동작까지 표현하도록 이 명세를 보완하였다. 그리고 명세된 프로토콜 상태 기계의 상호운용성과 안전성을 정형적으로 증명하였다. 우리는 먼저 제시한 정형적 명세가 OSPF 프로토콜의 표준 문서에 나타난 모든 상태들과 모든 천이 이벤트들을 표현하고 있어, 명세된 프로토콜 상태기계가 완전성을 가지고 있다는 사실을 보이고, 또한 상호운용성을 가짐을 증명하였다. 그리고 프로토콜의 동작의 안전성을 증명하기 위해, 생존성, 그리고 라이브락 부재를 정형적으로 증명하고, 교착상태 부재 역시 정형적으로 증명하였다. 결과적으로 OSPF 프로토콜이 일관성을 가진다는 사실을 보인다. 본 명세와 검증은 기존외 OSPF Version 2의 프로토콜 메커니즘을 그대로 계승한 OSPF Version 3에서도 유효하다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권5호
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• pp.8-15
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• 2010

The purpose of this research is to check the validation of an auto-analysis method combined with aqua regia digestion apparatus for improvement of water distillation method used as a fluorine test of soil. Fluorine contents of CaO used in the pretreatment course of water distillation method were 120 mg/kg ~ 5,064 mg/kg at the blank test, which was exceeded up to maximum 12.5 times of the soil standard, so it was estimated due to a effect of fluorine existing as impurities of CaO. The recovery test of the same samples indicated that water distillation method and auto-analysis method were 134.5mg/kg and 161.7mg/kg respectively, the recovery ratio of the latter was 16.8% higher than the formal. The validation test of two methods satisfied the standard, but auto analysis method was excellent more than distillation method. Also, auto analysis method could save a analysis time up to maximum 4.7 times by comparison with water distillation method.

• Nuclear Engineering and Technology
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• 제44권8호
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• pp.929-938
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• 2012

The Computerized Procedure System (CPS) is one of the primary operating support systems in the digital Main Control Room. The CPS displays procedure on the computer screen in the form of a flow chart, and displays plant operating information along with procedure instructions. It also supports operator decision making by providing a system decision. A procedure flow should be correct and reliable, as an error would lead to operator misjudgment and inadequate control. In this paper we present a modeling for the CPS that enables formal verification based on Petri nets. The proposed State Token Petri Nets (STPN) also support modeling of a procedure flow that has various interruptions by the operator, according to the plant condition. STPN modeling is compared with Coloured Petri net when they are applied to Emergency Operating Computerized Procedure. A converting program for Computerized Procedure (CP) to STPN has been also developed. The formal verification and validation methods of CP with STPN increase the safety of a nuclear power plant and provide digital quality assurance means that are needed when the role and function of the CPS is increasing.

• 한국컴퓨터정보학회논문지
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• 제18권1호
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• pp.123-136
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• 2013

시각적이고 비정형적인 구조로 표현된 휘처 모델(Feature model)은 구문적 명확성을 보장할 수 없고, 자동화 툴(tool)에 의한 구문(syntax)의 검증이 어렵다. 따라서, 휘처 모델이 가진 구조물의 구문적 명확성을 입증하기 위한 정형적 명세와 모델 검사(model checking)가 필요하다. 본 논문은 Z 언어를 이용한 휘처 모델의 정형적 명세와 모델 검사를 통해서, 휘처 모델의 정확성을 검사하는 기법을 제시한다. 이를 위해, 휘처 모델과 Z간 변환 규칙을 정의하고, 이 규칙에 의거하여 휘처 모델의 구문에 대해 Z 스키마(schema)로 명세한다. 모델 검사는 Z 스키마 명세에 대해 Z/Eves 툴을 사용하여 구문, 타입 검사(type checking), 그리고 도메인 검사(domain checking)를 수행하여 모델의 모호성을 검사한다. 이로서, 휘처 모델의 구조물을 좀더 명확하게 표현할 수 있으며, 설계된 모델의 오류를 검사할 수 있다.

• Nuclear Engineering and Technology
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• 제31권2호
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• pp.157-171
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• 1999

In this work, an automatic software verification method for Nuclear Power Plant (NPP) protection system is developed. This method utilizes Colored Petri Net (CPN) for system modeling and Prototype Verification System (PVS) for mathematical verification. In order to help flow-through from modeling by CPN to mathematical proof by PVS, an information extractor from CPN models has been developed in this work. In order to convert the extracted information to the PVS specification language, a translator also has been developed. ML that is a higher-order functional language programs the information extractor and translator. This combined method has been applied to a protection system function of Wolsong NPP SDS2(Steam Generator Low Level Trip). As a result of this application, we could prove completeness and consistency of the requirement logically. Through this work, in short, an axiom or lemma based-analysis method for CPN models is newly suggested in order to complement CPN analysis methods and a guideline for the use of formal methods is proposed in order to apply them to NPP Software Verification and Validation.

• Industrial Engineering and Management Systems
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• 제14권1호
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• pp.88-93
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• 2015

In this paper, we identify the characteristics of modeling and simulation (M&S) for military and defense and propose the method of verification, validation, and accreditation (VV&A) using the identified characteristics. M&S has been widely used for many different applications in military and defense, including training, analysis, and acquisition. Various methods and processes of VV&A have been proposed by researchers and M&S practitioners to guarantee the correctness of M&S. The notion of applying formal credibility assessment in VV&A originated in software engineering reliability testing and the systems engineering development process. However, the VV&A techniques and processes proposed for M&S by the research community have not addressed the characteristics and issues specific to military and defense. We first identify the characteristics and issues of military/defense M&S and then propose techniques and methods for VV&A that are specific for military/defense M&S. Possible approaches for the development of VV&A are also proposed.